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Race, Obesity, Poverty, and IQ

2100 words

America has a current and ongoing obesity epidemic. Some ethnicities are more likely to be obese or overweight than others due to lower intelligence which means a lack of ability to delay gratification, lack of ability to think into the future, lower funds which translates to eating more refined carbohydrates which means more blood glucose spikes which then leads to obesity as I will show. Insulin has a causal relationship with obesity so those who lack funds to buy healthier food then turn to refined foods high in carbohydrates as they are cheaper and more abundant in low-income neighborhoods.

Adult obesity rate by State (top 5) is: 1) Louisiana (36.2 percent), 2) Alabama (35.6), West Virginia (35.6), and Mississippi (35.6), and 5) Kentucky (34.6) with the 5 least obese States being 51) Colorado (20.2), 49) Hawaii (20.7), 48) Montana (23.6), 47) California (23.2), and 46) Massachusetts (24.3). Notice how the States with higher rates of obesity are in the South and the States with the lower rates are in the North, give or take. The average IQ for these States as follows: Lousiana: 95.3, Alabama: 95.7, West Virginia 98.7, Mississippi 94.2 (lowest IQ State in the country, largest black population at 37 percent), and Kentucky at 99.4. The average IQ for those States is 96.66. The average IQs for the States with the lowest obesity rates are: Colorado 101.6, Hawaii 95.6, Montana 103.4, California 95.5, and Massachusets 104.3 (highest IQ State). The average for these States being 100.08. So there is a 4 point IQ difference between the top 5 States with the highest and lowest percentage of obese people, which goes with the North/South gradient of higher IQ people living in the North and lower IQ people living in the South. Back in 2014, a California real estate group took 500,000 Tweets using a computer algorithm and estimated intelligence based on spelling, grammar, and word choice and found a difference in State by State intelligence. Notice how the further North you go the higher the average intelligence is, which is then correlated with the obesity levels in that State.

With poverty rates by State, we can see how the States in the South have less intelligent people in them which then correlates to the amount of obesity in the State. Though, there are some anomalies. West Virginia and Kentucky have a super majority of whites. This is easily explained by the fact that less intelligent whites live in those States, and since both the poverty rates and obesity rates are high, it follows that the State will be less intelligent than States that have more intelligent people and less obesity.

It is known that intelligence is correlated with obesity at around -.25 (Kanazawa, 2014). The negative correlation between intelligence and obesity means that they are inversely related so, on average, one with higher intelligence has less of a chance of being obese than one with lower intelligence. The States with the lowest IQ people having those with the highest BMIs corroborates this. In America, obesity rates by ethnicity are as follows: 67.3% for whites, 75.6% for blacks, and 77.9% for ‘Hispanics’.

Now that we know the average intelligence rates by State, the percentage of obese by State and the demographics by State, we can get into why obesity rates correlate with intelligence and race.

Diaz et al (2005) showed that minority populations are more likely to be affected by diabetes mellitus which may be due to less healthy diets and/or genetic factors. Using the National Health and Nutrition Survey for 1999-2000, they analyzed overweight, healthy adults, calculating dietary intake variables and insulin sensitivity by ethnicity. They characterized insulin resistance with fasted insulin, as those who are more likely to become insulin resistant have higher fasted insulin levels (levels taken after waking, with the subject being told not to eat the night before as to get a better reading of fasted insulin levels). Non-‘Hispanic’ whites had higher energy and fat intake while ‘Hispanics’ had higher carb intake with blacks having lower fiber intake.  Blacks and ‘Hispanics’ were more likely to have lower insulin sensitivity. However, ‘Hispanics’ were more likely to have lower insulin sensitivity even after controlling for diet, showing that metabolic differences exist between ethnicities that affect carbohydrate metabolism which leads to higher rates of diabetes in those populations.

Drewnowski and Specter (2004) showed that 1) the highest rates of obesity are found in populations with the lowest incomes and education (correlated with IQ), 2) an inverse relationship between energy density and energy cost, 3) sweets and fats have higher energy density and are more palatable (food scientists work feverishly in labs to find out different combinations of foods to make them more palatable so we will eat more of them), and 4) poverty and food insecurity are associated with lower food expenditures, lower fruit and vegetable intake, and lower-quality diet. All of these data points show that those who are poor are more likely to be obese due to more energy-dense food being cheaper and fats and sugars being more palatable.

Now that I’ve shown the relationship between race and IQ by state, obesity rates by state, insulin sensitivity by race, and that those in poverty are more likely to be obese, I can now talk about the actual CAUSE of obesity: insulin.

The conventional wisdom is that if you consume more kcal than you expend, you will gain weight, whereas if you consume less than your daily needs you will lose weight. This has been unchallenged for 50 years. Also known as Calories In and Calories Out (CICO), this mantra “eat less and move more!!!” has been bleated over and over with horrendous results. The CICO model only concerns itself with calories and not insulin which is a causal factor in obesity

In this study, participants in the basal insulin group which received the lowest average insulin dose gained the least average amount of weight at 4.2 pounds. Those on prandial insulin gained the most weight at 12.5 pounds. The intermediate group gained 10.3 pounds. More insulin, more weight gain. Moderate insulin, moderate weight gain. Low insulin, low weight gain.

Researchers compared a standard dose of insulin to tightly control blood sugars in type 1 diabetic patients. At the end of the 6 years, the study proved that intensive control of blood sugars resulted in fewer complications for those patients.

Though, in the high dose group, they gained on average 9.8 pounds more than those in the standard group.

More than 30 percent experienced major weight gain! Prior to the study, both groups were equal in weight. But the only difference was the amount of insulin administered. Were the ones given high levels of insulin all of a sudden more lazy? Were those who gained weight suddenly lacking in willpower? Were they lazier before the study? We’re they more gluttonous? No, no, and no!!



Finally, Henry et al (1993) took Type II diabetics and started them off with no insulin. They went from 0 units of insulin a day to 100 units at 6 months. As higher rates of insulin were administered, weight rose in the subjects. Insulin was given, people gained weight. A direct causal relationship (see figure above). However, what’s interesting about this study is that the researchers measured the amount of kcal ingested, the number of kcal ingested was reduced to 300 per day. Even as they took in less kcal, they gained 20 pounds! What’s going on here? Well, insulin is being administered and if you know anything about insulin it’s one of the hormones in the body that tells the body to either store fat or not burn it for energy. So what is occurring is the body is ramping down its metabolism in order for the subject to store more fat due to the exogenous insulin administered. Their TDEE dropped to about 1400 kcal, while they should have been losing weight on 1700 kcal! The CICO model predicts they should have lost weight, however, adaptive thermogenesis, better known as metabolic slow down, occurred which dropped the TDEE in order for the body to gain fat, as insulin directly causes obesity by signaling the body to store fat, so the body drops its metabolism in an attempt to do so. 

Putting this all together, blacks and ‘Hispanics’ are more likely to be in poverty, have lower intelligence, and have higher rates of obesity and diabetes. Furthermore, blacks are more likely to have metabolic diseases (adaptive thermogenesis aka metabolic slowdown is a metabolic disease) which are related with obesity due to their muscle fiber typing which leads to lower maximal aerobic capacity (less blood and oxygen get around the body). Type II skeletal muscle fibers’ metabolic profile contributes to lower average aerobic capacity in blacks. It also is related to cardiometabolic diseases, in my opinion because they don’t have the muscle fiber typing to run long distances, thus increasing their aerobic capacity and VO2 max.

Due to the diets they consume, which, due to being in poverty and having lower intelligence, they consume more carbohydrates than whites, which jacks their blood glucose levels up and the body then releases insulin to drive the levels glucose in the body down. As insulin levels are spiked, the body becomes insulin resistant due to the low-quality diet. Over time, even a change in diet won’t fix the insulin resistance in the body. This is because since the body is insulin resistant it created more insulin which causes insulin resistance, a vicious cycle.

Poverty, intelligence and race both correlate with obesity, with the main factor being lower intelligence. Since those with lower IQs have a lack of foresight into the future, as well as a lower ability to delay gratification which also correlates with obesity, they cannot resist low-quality, high-carb food the same way one with a higher IQ can. This is seen with the Diaz et al study I linked, showing that whites have higher levels of fat intake, which means lower levels of carbohydrate intake in comparison to blacks and ‘Hispanics’. As I’ve shown, those in poverty (code word for low intelligence) ingest more refined carbohydrates, they have higher levels of obesity due to the constant spiking of their insulin, as I have shown with the 3 aforementioned studies. Since blacks and ‘Hispanics’ have lower levels of intelligence, they have lower levels of income which they then can only afford cheap, refined carbs. This leads to insulin being constantly spiked, and with how Americans eat nowadays (6 times a day, 3 meals and snacks in between), insulin is being spiked constantly with it only dipping down as the body goes into the fasted state while sleeping. This is why these populations are more likely to be obese, because they spike their insulin more. The main factor here, of course, is intelligence.

Another non-CICO cause for obesity is exposure to BPA in the womb. Researchers carried out BPA testing in three differing subjects: 375 babies invitro, (3rd trimester) children aged 3 (n=408) and aged 5 (n=518) (Hoepner, et al, 2016). They measured the children’s bodies as well as measuring body fat levels with bioelectrical impedance scales.Prenatal urinary BPA was positively associated with waist circumference as well as fat mass index, which was sex-specific. When analyzed separately, it was found that there were no associated outcomes in body fat for boys (however it does have an effect on testosterone), but there was for girls (this has to do with early onset puberty as well). They found that after controlling for SES and other environmental factors there was a positive correlation with fat mass index – a measure of body fat mass adjusted for height, body fat percentage and waist circumference. The researchers say that since there was no correlation between BPA and increased obesity, that prenatal exposure to BPA indicates greater vulnerability in that period. The sample was of blacks and Dominicans from New York City. Whites drink less bottled water, which has higher levels of BPA. Blacks and ‘Hispanics’ consume more, and thus have higher levels of obesity.

In conclusion, blacks and ‘Hispanics’ are more likely to be in poverty, have lower intelligence, higher rates of obesity and lower incomes. Due to lower incomes, cheap, refined carbohydrates is what they can afford in bulk as that’s mostly what’s around poor neighborhoods. Ingesting refined carbohydrates more often consistently jacks up blood glucose which the body then releases insulin to lower the levels. Over time, insulin resistance occurs, which then leads to obesity. As I’ve shown, there is a direct causal relationship between the amount of insulin administered and weight gain. With the aforementioned factors with these two populations, we can see how the hormonal theory of obesity fits in perfectly with what we know about these ethnic groups and the obesity rates within them. Since people in poverty gravitate more towards cheap and refined carbohydrates, they’re constantly spiking their insulin which, over time, leads to insulin resistance and obesity.


Blood Pressure, Stress, and the Social Environment: On Black-White Differences in Blood Pressure

1800 words

Blood pressure (BP) is a physiological variable. Therefore since it is a physiological variable then it can be affected by environmental and social changes. How do racial differences come into play here, for instance? Since blacks face more (perceived) discrimination, then they should, on average, have higher BP levels than whites. This is what we find—but the effect is mostly seen in low-income blacks. How do psychosocial factors come into play here in the black-white BP gap?

BP is regulated by cardiac output, vascular resistance of blood flow, blood volume, arterial stiffness, and, of course, the individual’s emotional state which can decrease or increase BP. Neural mechanisms also exist which regulate BP (Chopra, Baby, and Jacob, 2011). Knowing how and why BP increases or decreases will have us better understand the social contexts of increased BP in low SES blacks.

BP is a complex physiological trait. It can go up and down due to what occurs in the immediate environment. Values of 120/80 mmHg are cited as ‘average’ values, but we have no idea what an ‘average’ BP is. Nevertheless—like most/all physiological variables—there is a wide range of what is considered ‘normal’. Due to the variance in human physiological systems, what is ‘normal’ for one individual is not ‘normal’ for another. Variation in BP (like, say, 120 SBP (systolic blood pressure) to 140 SBP) is ‘normal’. I believe even around 110 for SBP is within that range. For DPB (diastolic blood pressure) between 75 and 90 is within normal diurnal fluctuations due to activity/eating/etc (Taylor, Wilt, and Welch, 2011). BP, like testosterone, is one of those tricky variables to measure and so must be measured upon waking to see if there are any problems. So even for a trait like BP, there seems to be a ‘normal range’.

About 33 percent of blacks have hypertension (HTN) (Peters, Arojan, and Flack, 2006). Urban blacks are more likely to have higher BP levels than whites, but “At present, there is no complete explanation for these differences and further research is required” (Lindhorst et al, 2007). Low SES is correlated with higher levels of BP in black Americans—especially those with darker skin—but not Africans in Africa (Fuchs, 2011), suggesting that this is an American phenomenon that needs to be addressed. One good explanation, in my view, is the social environment. Physiological traits are extremely malleable due to the need to be able to ‘change gears’ in an instant, for instance to either fight or flight. Though, in our modernized world, these responses—mostly—have no need and so (due to our supposed civilized behavior), one’s BP rises due to social stress and other environmental factors and it is due to the urban environment.

What is the cause of high BP in blacks?

One explanation that has been given to explain higher rates of BP in blacks when compared to whites is discrimination. However, studies show mixed evidence on whether or not so-called discrimination raises BP (Couto, Goto, and Bastos, 2012). The same American effect (American blacks having higher BP than American whites) is seen even in the UK London area (Agyemang and Bhopal, 2003). This, yet again, is more evidence that the social environment drives these differences—again, regardless of whether or not any of the discrimination is real or imagined. Say most of it were imagined: it’d be irrelevant because the imagined discrimination leads to very real physiological outcomes in BP. 

The country of birth also has an effect on BP. In one study, it was noted that Africans had significantly higher BP when compared to Asians (which is identical/lower) and native French living in France (Bahous et al, 2015). Ethnic differences in BP increase due to similar sodium intake is lower than what is usually cited (Graudal and Jurgens, 2015). However, other authors have pointed out that basing conclusions off of observational studies have problems, like the estimation of sodium intake being inaccurate since it’s a one-time measure;  (Gunn et al, 2013; Cobb et al, 2014)

There is also evidence—along with pathways—that show how certain social activities work to lower stress and BP, including participation at church (Livingstone, Devine, and Moore, 1991). Black Americans can make other lifestyle changes in order to decrease BP, such as exercise and other lifestyle interventions. Redman, Baer, and Hicks state that “gene-environment interactions, job-related stress, racism, and other psychosocial factors to racial/ethnic disparities” need to be explored as causes for higher rates of HTN in blacks compared to whites. And with the knowledge of how all physiological systems work in terms of stress and other factors, should be explored as causes for this disparity.

Grim et al (1990) state that factors that influence high BP in blacks compared to whites are inherited and that is the major source of variation between these populations. However, the other mounting social/physiological evidence deserves an explanation; that is not inherited, and what we know about how our physiology responds to stress and discrimination—whether real or imagined—are extremely important and lead to extremely real, and important, outcomes in these populations. It is also argued that since blacks en route to America during the slave trade died from salt-depletive diseases, that blacks with a higher genetic propensity to absorb salt survived and this is why blacks have a higher propensity to absorb salt and are more ‘salt-sensitive’, which also could explain higher rates of HTN in American blacks compared to their cousins in Africa (Wilson and Grim, 1991). However, Curtin (1992) disputes this because “There is no evidence that diet or the resulting patterns of disease and demography among slaves in the American South were significantly different from those of other poor southerners”.

However, in regards to the social environment, Williams (1992) drives one of the best arguments I have encountered in this literature so far, stating that while genetic factors play a small part in regards to the BP gap between blacks and whites, social factors are arguably more important than genetic ones (and with our homeodynamic physiology, this does make sense). Dressler (1990) for instance, argues that skin color is a proxy for both social class and discrimination and these factors explain a large amount of the variation. Psychosocial variables can also explain heightened BP (Marmot, 1985Cuffee et al, 2014). Yan et al (2003) also note how “time urgency/impatience” and “hostility” “were associated with a dose-response increase in the long-term risk of hypertension.” Henry (1988) also argues that calcium, obesity and genetic factors cannot be the aetiology of HTN in blacks, while also proposing that high sodium intakes are due to psychosocial stress (Williams, 1992: 136).

Obesity also leads to hypertension (Re, 2009) while blacks are more likely to be obese than whites, however, black American men with more African ancestry are less likely to be obese (Klimentidis et al, 2016). This would imply that the greater amount of African ancestry in American blacks both protects against obesity and along with it HTN. Williams (1992) makes a convincing argument that environmental and social factors are the cause for the black-white BP gap. And while genetic factors are important, no doubt, environmental  and social factors are arguably more important to this debate.

Kulkarni et al (1998) show that increased stress leads to subsequent BP elevations which, over time, will lead to HTN. In a 2009 meta-analysis, Gasparin et al show how “individuals who had stronger responses to stressor tasks were 21% more likely to develop blood pressure increase when compared to those with less strong responses.”

Further, in support for the ‘perceived stress’ hypothesis in regards to blacks ‘perceiving’ stress and discrimination, “stress denial in combination with abdominal obesity, alcohol consumption, and smoking may be proxy for a high stress level” (Suter et al, 1997). Carroll et al (2001) also show how there are is “modest support for the hypothesis that heightened blood pressure reactions to mental stress contribute to the development of high blood pressure.Sparrenberger et al (2009) also did a systematic review of observational studies, finding that “Acute stress is probably not a risk factor for hypertension. Chronic stress and particularly the non-adaptive response to stress are more likely causes of sustained elevation of blood pressure.

Lastly, Langford (1981) shows that when SES is controlled for, the black-white BP disparity vanishes, implying that social and environmental—not genetic—factors are the cause for elevated HTN levels in black Americans. Sweet et al (2007) showed that for lighter-skinned blacks, as SES rose BP decreased while for darker-skinned blacks BP increased as SES did while implicating factors like ‘racism’ as the ultimate causes. This is solid evidence that both skin color and SES are predictors of higher prevalence of BP in black populations, and since other studies show that this is not noticed in higher class blacks, nor is this noticed in blacks in Africa, then the main causes of this disparity are social and environmental in nature.

(Non, Gravlee, and Mulligan, 2012). Their study suggests that educating black Americans on the dangers and preventative measures of high BP will reduce BP disparities between the races. This is in-line with Williams (1992) in that the social environment is the cause for the higher rates of BP. One hypothesis explored to explain why this effect with education was greater in blacks than whites was that BP-related factors, such as stress, poverty and racial discrimination (remember, even if no racial discrimination occurs, any so-called discrimination is in the eye of the beholder so that will contribute to a rise in physiologic variables) and maybe social isolation may be causes for this phenomenon. Future studies also must show how higher education causes lower BP, or if it only serves as other markers for the social environment. Nevertheless, this is an important study in our understanding of how and why the races differ in BP and it will go far to increase our understanding of this malady. This is a very convincing argument that education and not genetic ancestry cause disparities in BP between blacks and whites.

WebMD states that, of course, both environmental and genetic factors are at play in regards to black’s increased propensity for acquiring HTN. Fuchs (2011) also states that “They [environmental and behavioral factors] could act directly or by triggering mechanisms of blood pressure increase that are dormant in blacks living in Africa” and explain why black Americans have higher rates of BP than Africans in Africa. Further, race and ethnicity are independent predictors of HTN (Holmes et al, 2013).


Blacks and whites do differ in BP, and its aetiology is both complex and hard to untangle Genetic factors probably don’t account for a lot of this variance since Africans in Africa have low levels of BP compared to their black American cousins. Numerous lines of evidence shows that social and environmental factors are the cause, and so to change this, all people—especially blacks—should be educated on how to change these problems in our society. Whether discrimination is real or imagined, the effects of it lead to real physiological outcomes that then lead to increased health disparities between these populations.

Race and Medicine: Is Race a Useful Category?

2450 words

The New York Times published an article on December the 8th titled What Doctors Should Ignore: Science has revealed how arbitrary racial categories are. Perhaps medicine will abandon them, too. It is an interesting article and while I do not agree with all of it, I do agree with some.

It starts off by talking about sickle cell anemia (SCA) and how was once thought of as a ‘black disease’ because blacks were, it seemed, the only ones who were getting the disease. I recall back in high-school having a Sicilian friend who said he ‘was black’ because Sicilians can get SCA which is ‘a black disease’, and this indicates ‘black genes’. However, when I grew up and actually learned a bit about race I learned that it was much more nuanced than that and that whether or not a population has SCA is not based on race, but is based on the climate/environment of the area which would breed mosquitoes which carry malaria. SCA still, to this day, remains a selective factor in the evolution of humans; malaria selects for the sickle cell trait (Elguero et al, 2015).

This is a good point brought up by the article: the assumption that SCA was a ‘black disease’ had us look over numerous non-blacks who had the sickle cell trait and could get the help they needed, when they were overlooked due to their race with the assumption that they did not have this so-called ‘black disease’. Though it is understandable why it got labeled ‘a black disease’; malaria is more prevalent near to the equator and people whose ancestors evolved there are more likely to carry the trait. In regards to SCA, it should be known that blacks are more likely to get SCA, but just because someone is black does not automatically mean that it is a foregone conclusion that one has the disease.

The article then goes on to state that the push to excise race from medicine may undermine a ‘social justice concept’: that is, the want to rid the medical establishment of so-called ‘unconscious bias’ that doctors have when dealing with minorities. Of course, I will not discount that this doesn’t have some effect—however small—on racial health disparities but I do not believe that the scope of the matter is as large as it is claimed to be. This is now causing medical professionals to integrate ‘unconscious bias training’, in the hopes of ridding doctors of bias—whether conscious or not—in the hopes to ameliorate racial health disparities. Maybe it will work, maybe it will not, but what I do know is that if you know someone’s race, you can use it as a roadmap to what diseases they may or may not have, what they may or may not be susceptible to and so on. Of course, only relying on one’s race as a single data point when you’re assessing someone’s possible health risks makes no sense at all.

The author then goes on to write that the terms ‘Negroid, Caucasoid, and Mongoloid’ were revealed as ‘arbitrary’ by modern genetic science. I wouldn’t say that; I would say, though, that modern genetic science has shown us the true extent of human variation, while also showing that humans cluster into 5 distinct geographic categories, which we can call ‘race’ (Rosenberg et al, 2002; but see Wills, 2017 for alternative view that the clusters identified by Rosenberg et al, 2002 are not races. I will cover this in the future). The author then, of course, goes on to use the continuum fallacy stating that since “there are few sharp divides where one set of traits ends and another begins“. A basic rebuttal would be, can you point out where red and orange are distinct? How about violet and blue? Blue and Cyan? Yellow and orange? When people commit the continuum fallacy then the only logical conclusion is that if races don’t exist because there are “few sharp divides where one set of traits ends and another begins“, then, logically speaking, colors don’t exist either because there are ‘few [if any] sharp divides‘ where one color ends and another begins.


The author also cites geneticist Sarah Tishkoff who states that the human species is too young to have races as we define them. This is not true, as I have covered numerous times. The author then cites this study (Ng et al, 2008) in which Craig Venter’s genome was matched with the (in)famous [I love Watson] James Watson and focused on six genes that had to do with how people respond to antipsychotics, antidepressants, and other drugs. It was discovered that Venter had two of the ‘Caucasian’ variants whereas Watson carried variants more common in East Asians. Watson would have gotten the wrong medicine based on the assumption of his race and not on the predictive power of his own personal genome.

The author then talks about kidney disease and the fact that blacks are more likely to have it (Martins, Agodoa, and Norris, 2012). It was assumed that environmental factors caused the disparity of kidney disease in blacks when compared to whites, however then the APOL1 gene variant was discovered, which is related to worse kidney outcomes and is in higher frequencies in black Americans, even in blacks with well-controlled blood pressure (BP) (Parsa et al, 2013). The author then discusses that black kidneys were seen as ‘more prone to failure’ than white kidneys, but this is, so it’s said, due to that one specific gene variant and so, race shouldn’t be looked at in regards to kidney disease but individual genetic variation.

In one aspect of the medical community can using medicine based on one’s race help: prostate cancer. Black men are more likely to be afflicted with prostate cancer in comparison to whites (Odedina et al, 2009; Bhardwaj et al, 2017) with it even being proposed that black men should get separate prostate screenings to save more lives (Shenoy et al, 2016). Then he writes that we still don’t know the genes responsible, however, I have argued in the past that diet explains a large amount—if not all of the variance. (It’s not testosterone that causes it like Ross et al, 1986 believe).

The author then discusses another medical professional who argues that racial health disparities come down to the social environment. Things like BP could—most definitely—be driven by the social environment. It is assumed that the darker one’s skin is, the higher chance they have to have high BP—though this is not the case for Africans in Africa so this is clearly an American-only problem. I could conjure up one explanation: the darker the individual, the more likely he is to believe he is being ‘pre-judged’ which then affects his state of mind and has his BP rise. I discussed this shortly in my previous article Black-White Differences in PhysiologyWilliams (1992) reviewed evidence that social, not genetic, factors are responsible for BP differences between blacks and whites. He reviews one study showing that BP is higher in lower SES, darker-skinned blacks in comparison to higher SES blacks whereas for blacks with higher SES no effect was noticed (Klag et al, 1991). Sweet et al (2007) showed that for lighter-skinned blacks, as SES rose BP decreased while for darker-skinned blacks BP increased as SES did while implicating factors like ‘racism’ as the ultimate causes.

There is evidence for the effect of psychosocial factors and BP (Marmot, 1985). In a 2014 review of the literature, Cuffee et al (2014) identify less sleep—along with other psychosocial factors—as another cause of higher BP. It just so happens that blacks average about one hour of sleep less than whites. This could cause a lot of the variation in BP differences between the races, so clearly in the case of this variable, it is useful to know one’s race, along with their SES. Keep in mind that any actual ‘racism’ doesn’t have to occur; the person only ‘needs to perceive it’, and their blood BP will rise in response to the perceived ‘racism’ (Krieger and Sidney, 1996). Harburg et al (1978) write in regards to Detroit blacks:

For 35 blacks whose fathers were from the West Indies, pressures were higher than those with American-born fathers. These findings suggest that varied gene mixtures may be related to blood pressure levels and that skin color, an indicator of possible metabolic significance, combines with socially induced stress to induce higher blood pressures in lower class American blacks.

Langford (1981) shows that when SES differences are taken into account that the black-white BP disparity vanishes. So there seems to be good evidence for the hypothesis that psychosocial factors, sleep deprivation, diet and ‘perceived discrimination’ (whether real or imagined) can explain a lot of this gap so race and SES need to be looked at when BP is taken into account. These things are easily changeable; educate people on good diets, teach people that, in most cases, no, people are not being ‘racist’ against you. That’s really what it is. This effect holds more for darker-skinned, lower-class blacks. And while I don’t deny a small part of this could be due to genetic factors, the physiology of the heart and how BP is regulated by even perceptions is pretty powerful and could have a lot of explanatory power for numerous physiological differences between races and ethnic groups.

Krieger (1990) states that in black women—not in white women—“internalized response to unfair treatment, plus non-reporting of race and gender discrimination, may constitute risk factors for high blood pressure among black women“. This could come into play in regards to black-white female differences in BP. Thomson and Lip (2005) show that “environmental influence and psychosocial factors may play a more important role than is widely accepted” in hypertension but “There remain many uncertainties to the relative importance and contribution of environmental versus genetic influences on the development of blood pressure – there is more than likely an influence from both. However, there is now evidence to necessitate increased attention in examining the non-genetic influences on blood pressure …” With how our physiology evolved to respond to environmental stimuli and respond in real time to perceived threats, it is no wonder that these types of ‘perceived discrimination’ causes higher BP in certain groups with lower SES.

Wilson (1988) implicates salt as the reason why blacks have higher BP than whites. High salt intake could affect the body’s metabolism by causing salt retention which influences blood plasma volume, cardiac output. However, whites have a higher salt intake than blacks, but blacks still ate twice the recommended amounts from the dietary guidelines (all ethnic subgroups they analyzed from America over-consumed salt as well) (Fulgoni et al, 2014). Blacks are also more ‘salt-sensitive’ than whites (Sowers et al 1988Schmidlin et al, 2009; Sanada, Jones, and Jose, 2014) which is also heritable in blacks (Svetke, McKeown, and Wilson, 1996). A slavery hypothesis does exist to explain higher rates of hypertension in blacks, citing salt deficiency in the parts of Africa that supplied the slaves to the Americas, to the trauma of the slave trade and slavery in America. However, historical evidence does not show this to be the case because “There is no evidence that diet or the resulting patterns of disease and demography among slaves in the American South were significantly different from those of other poor southerners” (Curtin, 1992) whereas Campese (1996) hypothesizes that blacks are more likely to get hypertension because they evolved in an area with low salt.

The NYT article concludes:

Science seeks to categorize nature, to sort it into discrete groupings to better understand it. That is one way to comprehend the race concept: as an honest scientific attempt to understand human variation. The problem is, the concept is imprecise. It has repeatedly slid toward pseudoscience and has become a major divider of humanity. Now, at a time when we desperately need ways to come together, there are scientists — intellectual descendants of the very people who helped give us the race concept — who want to retire it.

Race is a useful concept. Whether in medicine, population genetics, psychology, evolution, physiology, etc it can elucidate a lot of causes for differences between races and ethnic groups—whether or not they are genetic or psychosocial in nature. That just attests to both the power of suggestion along with psychosocial factors in regards to racial differences in physiological factors.

Finally let’s see what the literature says about race in medicine. Bonham et al (2009) showed that both black and white doctors concluded that race is medically relevant but couldn’t decide why however they did state that genetics did not explain most of the disparity in relation to race and disease aside from the obvious disorders like Tay Sachs and sickle cell anemia. Philosophers accept the usefulness of race in the biomedical sciences (Andreason, 2009Efstathiou, 2012; Hardimon, 2013Winther, Millstein, and Nielsen, 2015; Hardimon, 2017) whereas Risch et al (2002) and Tang et al (2002) concur that race is useful in the biomedical sciences. (See also Dorothy Roberts’ Ted Talk The problem with race-based medicine which I will cover in the future). Richard Lewontin, naturally, has hang-ups here but his contentions are taken care of above. Even if race were a ‘social construct‘, as Lewontin says, it would still be useful in a biomedical sense; but since there are differences between races/ethnic groups then they most definitely are useful in a biomedical sense, even if at the end of the day individual variation matters more than racial variation. Just knowing someone’s race and SES, for instance, can tell you a lot about possible maladies they may have, even if, utltimately, individual differences in physiology and anatomy matter more in regards to the biomedical context.

In conclusion, race is most definitely a useful concept in medicine, whether race is a ‘social construct’ or not. Just using Michael Hardimon’s race concepts, for instance, shows that race is extremely useful in the biomedical context, despite what naysayers may say. Yes, individual differences in anatomy and physiology trump racial differences, but just knowing a few things like race and SES can tell a lot about a particular person, for instance with blood pressure, resting metabolic rate, and so on. Denying that race is a useful concept in the biomedical sciences will lead to more—not less—racial health disparities, which is ironic because that’s exactly what race-deniers do not want. They will have to accept a race concept, and they would accept Hardimon’s socialrace concept because that still allows it to be a ‘social construct’ while acknowledging that race and psychosocial factors interact to cause higher physiological variables. Race is a useful concept in medicine, and if the medical establishment wants to save more lives and actually end the racial disparities in health then they should acknowledge the reality of race.

Race and Nutrition

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What we eat is important. What we eat can increase or decrease our lifespan. But do different races digest and metabolize different macro and micronutrients differently? On a racial level in terms of individual diet, would one individual benefit from adopting the diet of their ancestors over another diet? Many claims have been made like this in the past few years, such as Europeans evolving to eat plants and grains. This, some people would presume, implies that if you have a certain ancestry then you must eat a certain diet or take different steps in regard to nutrition. I will show this is wrong and that, at least in regard to health and nutrition, individual variation matters more than racial variation (don’t call Lewontin’s fallacy on me. This is not a fallacy).

Different genetically isolated breeding populations evolved eating different diets based on what they had in their environment. Over time, humans eventually developed agriculture and then changed the course of human evolution forever (Cochran and Harpending, 2009). This then leads to large changes in how our genes are expressed and how our microbiome metabolizes nutrients and food we ingest. The advent of farming was, obviously, pivotal to human evolution (Cochran and Harpending, 2009). This then lead to heritable changes in the genome brought on by new foods the farmers ate. This also started the environmental mismatches we now have in our modern world, which is the cause for rising obesity rates and a large part of the cause of so-called diseases of civilization (for a discussion of these matters, see Taubes, 2008, chapter 5; see also page 8 in this summary of his book on diseases of civilization and also see Burkitt, 1973Cordain, Eades, and Eades, 2003; Sharma and Majumdar, 2009; Sikter, Rihmer, and Guevara, 2017. For an outstanding review on the subject, read Daniel Lieberman’s 2013 book The Story of the Human Body: Evolution, Health, and Disease for in-depth discussions on this point and more in regard to nutrition and our evolutionary history).

Studies come out all the time saying that X population evolved eating Y food therefore Z. Then, people not privy to nutrition science, jump to large sweeping conclusions (mostly laymen and journalists, who are also laymen). These assumptions imply that people’s metabolic systems aren’t, first and foremost, based on an individual level with individual variation in physiologic and metabolic traits. This, I will show, is the reason why these studies don’t mean you should change your diet to what your ancestors supposedly ate based on these studies (though as I have argued in the past, high consumption of processed foods lead to obesity, insulin resistance, diabetes etc which is the cause of a lot of the modern-day maladies currently present in our population today). This assumption is wrong on numerous levels.

Buckley et al (2017), using data from the 1000 Genomes Project (see also Via, Gignoux, and Burchard, 2010), identified novel potential selections in the FADs region. The 1000 Genomes Project tested the genomes of 101 Bronze Age Europeans. They show that SNPs which are associated with arachidonic acid and eicosapentaenoic acid has been favored in Europeans since the Bronze Age (the selection for arachidonic acid being due to milk consumption which is a form of niche construction; see Laland, Odling-Smee, and Feldman, 1999; Laland, Odling-Smee, and Feldman, 2001; Laland and Brown, 2006Rendell, Fogarty, and Laland, 2011Laland, et al, 2016; but see Gupta et al, 2017 for a different view which will be covered in the future). They also hypothesize that differences in the selection of these regions is different in different population, implying different epigenetic changes brought on by diet (more on this later).

The FADS1 gene codes for an enzyme called fatty acid desaturase 1 which desaturates n3 and n6 which then catalyzes eicosapentaenoic and Arachidonic acid (Park et al, 2009). These genes code for enzymes that then aid in the breakdown of fatty acids. So, by testing Bronze Age Europeans and comparing their genomes with modern-day Europeans, researchers can see how the expression of genes changed and then work backward and hypothesize how and why the differing gene expression occurred.

The regions selected for are involved in processing n3 and n6 fatty acids. We need a certain ratio of them, and if either is thrown out of whack then deleterious effects occur. This, of course, can be seen by comparing our ratio of n3 to n6 fatty acid consumption with our ancestors’, who ate a 1:1 ratio of n3 to n6 (Kris-Etherson et al, 2000) which you can then compare to our n3 to n6 ratio, which is 14 to 25 times higher than it should be. The authors state that n6 is important, but it’s only important to have the correct ratio, having too much n6 is not a good thing (as I have covered here).

Twenty percent of the dry weight of the brain is made up of long-chain polyunsaturated fatty acids (Lassek and Gaulin, 2009). Therefore it is pivotal we get the correct amount of n3 fatty acids for brain development both in vitro and during infancy, the best bet being to breastfeed the babe as the mother packs on fat during pregnancy so the babe can have PUfAs during its time on the womb as well as during infancy through breastfeeding.

About 85kya selective sweeping occurred in Africa on the FADs genes. Buckley et al (2017) write: “Humans migrating out of Africa putatively carried mostly the ancestral haplotype, which remained in high frequency in non-African populations, while the derived haplotype came close to fixation in Africa. It is unclear why positive selection for the derived haplotype appears to be restricted to Africa. Mathias et al. (2012) suggested that the emergence of regular hunting of large animals, dated to ∼50 kya, might have diminished the pressure for humans to endogenously synthesize LC-PUFAs.” This is true. There is a wealth of important fatty acids in the fatty and muscle tissue of animals, which we need for proper brain functioning and development.

They also write about a study on the Inuit that proves that certain alleles have been selected for that have to do with fatty acid metabolism, which I have also covered in the past in a response to Steve Sailer. Nevertheless, on a population level, this is worth it, but individual variation in metabolism matters more than population. In the article, Sailer implied—with a quote from  New York Times science editor Carl Zimmer—that the Inuit have certain gene variants that influence fatty acid metabolism in that population. Sailer goes on to write “So maybe you should try different diets and see if one works better for you.” Of course, you should. However individual variation is more important than racial variation. (It’s also interesting to note that these genes that are expressed on the Inuit are also related to height.)

Nevertheless, it is true that selection occurred on these parts of the genome in these populations studied by Buckley et al (2017), but to claim that all populations wouldn’t benefit from a low carb, high fat diet is not true. I do agree with Sailer on, in the future, the scanning of individual genomes to see which diet would have a better effect. Though I would insist that most, if not all, humans should eat a higher fat lower carb diet.

Buckley et al (2017) cite a study (Mathieson et al, 2015) which “provides strong evidence of selection in the FADSregion in Europe over the past 4,000 years, in addition to the patterns of selection already reported in Africans, South Asians, and the Inuit.Buckley et al (2017) also cite a study (Pan et al, 2017) which shows an SNP, rs174557, regulates FADS1.

In their analysis, they showed that “this variation is largely attributable to high differentiation between two haplotype clusters: a cluster widespread in Africa, largely containing derived alleles and possibly subject to a selective sweep (Mathias et al. 2011,, 2012), and an ancestral cluster, which is present across Eurasia.” They also showed that Neanderthal genomes cluster with the derived cluster, which is present in Africans, while Denisovans cluster with the ancestral cluster, which Eurasians also have.

Buckley et al (2017) write: “Thus the derived alleles appear to promote expression of FADS1 while simultaneously abating the expression of FADS2.” This is important to keep in mind for the end of this article when I talk about nutrition and how it affects the epigenome which can then become heritable in a certain population.

Buckley et al (2017) also confirm the results of the European sample using the Nurses Health Study and the Health Professionals follow-up study GWASs: “These results reinforce the associations with cholesterol from the GLGC GWAS. This confirms the hypothesized phenotypic effect of the selected variants in terms of increased EPA and ARA levels of the putatively positively selected variants in the European population.”

Selective (dietary) pressures on the three populations tested (Africans, Europeans and South Asians) have “have driven allele frequency changes in different FADS SNPs that are only in weak LD with each other [LD is linkage disequilibrium which is the nonrandom associations of alleles at different loci in a given population]” (Buckley et al, 2017). Further, the alleles (FADS1 and FADS2) that were under selection in Europeans were strongly associated with lipid metabolism, specifically reduced linoleic acid levels. An opposite pattern was noticed in the Inuit, where selection acted to “decrease conversion of SC-PUFAs to LC-PUFAs to compensate for the relative high dietary intake of LC-PUFAs.” The allele under selection was associated with a decrease in linoleic acid levels and an increase in eicosapentaenoic acid, which may possibly be due to improved metabolism in converting LC-PUFAs from SC-PUFAs.

Buckley et al (2017) hypothesize that the cause is eating a more plant-based diet which is rich in fatty acids (n6 and n3) while a subsequent decrease in fatty animal meats occurred. Of course, relative to hunter-gatherer populations, the increased plant consumption brought on by agriculture caused different methylation on the genome which then eventually became part of the heritable variation. So, of course, farmers would have eaten more plants and the like, which one then select for the production of SC-PUFAs to LC-PUFAs. This of course began at the dawn of agriculture (Cochran and Harpending, 2009).

Of course, this can help guide individual diets as we better map the human genome. These studies, for instance, can be used as guides for individual diets based on ancestral evolution. More studies, of course, are needed.

Also, in an email with correspondence with Arstechnica, one of the authors, Nelson Rasmussen, stated: “Of course, within the last century there have been drastic changes in the diets in many areas of Europe. Diets have typically become more caloric with a higher intake of simple sugars, and perhaps also more rich in proteins and fat from animals.  So selection is unlikely to be working in exactly the same way now.

Though the strong claim from Arstechnica that “This is another nail in the coffin for the scientific validity of paleo diets” is a strong claim which needs much more evidence because low carb high-fat diets are mostly best for people since their insulin levels aren’t spiked too much which then leads to obesity, diabetes and along with it hyperinsulinemia.

Now I need to talk about how epigenetics is involved here. Nutrition can alter the genome and epigenome (Niculescu and Lupu, 2011Niculescu, 2012; Anderson, Sant, and Dolinoy, 2012) and cause permanent heritable variation in a population if a certain allele reaches fixation, since there is evidence that maternal and paternal dietary changes possibly affecting multiple generations (Rosenfeld, 2017; though see Burggren, 2016 for the view that there is no evidence for heritable epigenetic phenotype in the genome. I will return to this in the future; see also the Dutch Famine Study showing heritable epigenetic change from famine; Lumey et al, 1993Heijmans, 2008; Stein et al, 2009Tobi et al, 2009; Schulz, 2010Lumey, Stein, and Susser, 2011; Hajj et al, 2014Jang and Serra, 2014; Tobi et al, 2014). Of course, based on what a population eats (or does not eat), epigenetic changes can and will occur. This not only affects the expression of genes in the body, but also the trillions of gut microbiota in our microbiome that partly drive our metabolic functions. Diet can change the composition of the microbiome, diet can change the epigenome and gene expression, and the microbiome can also up- and down-regulate genes (Hullar and Fu, 2014) Lipid metabolism is also related to developmental epigenetic programming (Marchlewicz et al, 2016). They showed that circulating fatty lipids in the mother during pregnancy are associated with DNA methylation in the genomes of the child. This can also, of course, contribute to health and disease risk in the future for the affected infant. FADS1 is also involved here.

Nutritional factors also come into play in regards to epigenetic inheritance (Alam et al, 2015). The n3 PUFAs also affect gene expression and DNA methylation (Hussey, Lindley, and Mastana, 2017). Further, DNA methylation is also associated with FADS1 and, to a lesser extent, FADS2 (Howard et al, 2014). This is strong evidence that, of course, that what was reviewed above in regards to selection for certain alleles for fatty acid metabolism in certain populations was strongly driven by the consumption of certain foods. Epigenetic changes that occur both in the womb and previous generations like the grandparents’, for instance, also have an effect in regard to which genes are expressed in the baby in vitro as well as consequences for future generations. The study of epigenetics, along with transgenerational epigenetic inheritance, of course, will be very important for our future understanding of both the evolution of humans and the evolution of the human diet.

Finally, I need to touch on why this doesn’t really matter in terms of individual diet choice. The fact of the matter is, anatomic, physiologic, and metabolic variation within race trumps variation between it. Two different randomly selected individuals will have different anatomy, along with different organs missing (Saladin, 2010). This implies that the individual differences in these traits trump whatever racial selection occurred since the dawn of agriculture 10kya. This is why, in my opinion, one should not look to just their ancestry when choosing a diet and should always choose a diet based that’s good for them, individually. Now, I’m not saying that this research is useless in regards to healthy diets, however, increased consumption of processed foods is the cause of obesity since processed foods (high in carbs) spike insulin which lead to obesity and diabetes (insulin causes weight gain). So, obviously, full-on plant-based diets will lead to these maladies. Contrary to the Alternative Hypothesis’ thesis on race and nutrition, this doesn’t really matter, not at the individual level, anyway. This could have small implications in regard to the population as a whole, but as an effect on the diet of individuals? No. Individual variation in traits matters much more than racial variation here (again, don’t call Lewontin’s fallacy because I’ve explained my reasoning which is logically sound).

In sum, the SNPs associated with the increased expression of FADs1 and increased the production of eicosapentaenoic and Arachidonic acid in Europeans occurred around 5kya. These studies are interesting to see how diet and how we construct our niches leads to changes in the genome based on those changes that we enact ourselves. However, laypersons who read these popular science articles on the evolution of diet in human populations will then assume that since they have X ancestry then they must eat how their immediate ancestors ate. The Arstechnica article makes some strong claims that Buckley et al (2017) prove that the paleo diet is not a viable solution for diseases of civilization. Do not make sweeping claims about eating X and Y because your ancestors evolved in Z environment, because individual variation in metabolic and physiologic functioning is greater and matters way more than racial variation

[Note: Diet changes under Doctor’s supervision only.]

MAOA, Race, and Crime: A Simple Relationship?

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When I first got into HBD back in 2012, one of the first things I came across—along with the research on racial IQs from Rushton, Lynn, Jensen et al—was that the races differed in a gene called MAOA-L, which has a frequency in Caucasians at .1 percent (Beaver et al, 2013), 54 percent in Chinese people (Lu et al, 2013; 56 percent in Maoris (Lea and Chambers 2007) while about 60-65 percent of Japanese people have the low-frequency version of this gene (Way and Lieberman, 2007).

So if these ethnies have a higher rate of this polymorphism and it is true that this gene causes crime, then the Chinese and Japanese should have the highest rates of crime in the world, since even apparently the effect of MAOA and violence and antisocial behavior is seen even without child abuse (Ficks and Waldman, 2014). Except East Asian countries have lower rates of crime (Rushton, 1995; Rushton and Whytney, 2002). Though, Japan’s low crime rate is relatively recent, and when compared with other countries on certain measures “Japan fares the same or worse when compared to other nations” (Barberet 2009, 198). This goes against a lot of HBD theory, and I will save that for another day. (Japan has a 99 percent prosecution rate, which could be due to low prosecutorial budgets; Ramseyer and Rasmusen, 2001. I will cover this in the future.)

The media fervor—as usual—gave the MAOA gene the nickname “the warrior gene“, which is extremely simplistic (I will have much more to say on ‘genes for’ any trait towards the end of the article). I will show how this is a very simplistic view.

The MAOA gene was first discovered in 1993 in a Dutch family who had a history of extreme violence going as far back as the 1890s. Since the discovery of this gene, it has been invoked as an ultimate cause of crime. However, as some hereditarians do note, MAOA only ’causes’ violence if one has a specific MAOA genotype and if they have been abused as a child (Caspi et al, 2002; Cohen et al, 2006; Beaver et al, 2009; Ferguson et al, 2011; Cicchetti, Rogosch, Thibodeau, 2012;). People have invoked these gene variants as ultimate causes of crime—that is, people who have the low-expressing MAOA variants are more likely to commit more crime—but the relationship is not so simple.

Maoris are more four times more likely to have the low-expressing gene variant than Europeans, the same holding for African Americans and Europeans (Lea and Chambers, 2007).

There is, however, a protective effect that protects whites (and not non-whites in certain cases) against antisocial behavior/violent attitudes if one has a certain genotype (Widom and Brzustowicz, 2006), though the authors write on page 688: “For non-whites, the effect of child abuse and neglect on the juvenile VASB was not significant (beta .08, SE .11, t 1.19, ns), whereas the effect of child maltreatment on lifetime VASB composite approached significance (beta .13, SE .12, t 1.86, p .06). For non-whites (see Figure 2), neither gene (MAOA) environment (child abuse and neglect) interaction was significant: juvenile VASB (beta .06, SE .28, t .67, ns) and lifetime VASB (beta .01, SE .29, t .14, ns).” So as you can see, there are mixed results. Whites seem to be protected against the effect of antisocial behavior and violence but only if they have a certain genotype (which implies that if they have the other genotype, then if abused they will show violent and antisocial behavior). So, we can see that the relationship between MAOA and criminal behavior is not as simple as some would make it out to be.

MAOA, like other genetic variants, of course, has been linked to numerous other traits. Steven J. Heine, author of the book DNA is Not Destiny: The Remarkable and Completely Misunderstood Relationship Between You and Your Genes:

However, any labels like “the warrior gene” are highly problematic because they suggest that the this gene is specifically associated with violence. It’s not, just as alleles from other genes do not only have one outcome. Pleiotropy is the term for how a single genetic variant can influence multiple different phenotypes. MAOA is highly pleiotropic: the traits and conditions potientially connected to the MAOA gene invlude Alzheimer’s. anoerxia, autism, body mass index, bone mineral density, chronic fatigue syndrome, depression, extraversion, hypertension, individualism, insomnia, intelligence, memory, neuroticism, obesity, openness to experience, persistence, restless leg syndrome, schizophrenia, social phobia, sudden infant death syndrome, time perception and voting behavior. (59) Perhaps it would be more fitting to call MAOA “the everything but the kitchen sink gene. (Heine, 2017: 195)

Something that I have not seen brought up when discussions of race, crime, and MAOA come up is that Japanese people have the highest chance—even higher than blacks, Maoris, and whites—to have the low repeat MAOA variant (Way and Lieberman) yet have lower rates of crime. So MAOA cannot possibly be a ‘main cause’ of crime. It is way more complex than that. “However intuitively satisfying it may be to explain cultural differences in violence in terms of genes“, Heine writes, “as of yet there is no direct evidence for this” (Heine, 2017: 196).

Numerous people have used ‘their genes’ in an attempt to get out of criminal acts that they have committed. A judge even knocked off one year off of a murder’s sentence since he found the evidence for the MAOA gene’s link to violence “particularly compelling.” I find it “particularly ridiculous” that the man got less time in jail than someone who ‘had a choice’ in his actions to murder someone. Doesn’t it seem ridiculous to you that someone gets less time in jail than someone else, all because he may have the ‘crime/warrior gene’?

Aspinwall, Brown, and Tabery (2012) showed that when evidence of a ‘biomechanic’ cause of violence/psychopathy was shown to the judges (n=191), that they reduced their sentences by almost one year if they were reading a story in which the accused was found to have the low-repeat MAOA allele (13.93 to 12.83 years). So, as you can see, this can sway judges’ perception into giving one a lighter sentence since they believe that the evidence shows that one ‘can not control themselves’, which results in the judge giving assailants lighter sentences because ‘it’s in their genes’.

Further, people would be more lenient on sentences for criminals who are found to have these ‘criminal genes’ than those who were found to not have them (Cheung and Heine, 2015). Monterosso, Royzman, and Schwartz (2010) also write: “Physiologically explained behavior was more likely to be characterized as “automatic,” and willpower and character were less likely to be cited as relevant to the behavior. Physiological explanations of undesirable behavior may mitigate blame by inviting nonteleological causal attributions.” So, clearly, most college students would give a lighter sentence if the individual in question were found to have ‘criminal genes’. But, if these genes really did ’cause’ crime, shouldn’t they be given heavier sentences to keep them on the inside more so those with the ‘non-criminal genes’ don’t have to suffer from the ‘genetically induced’ crime?

Heine (2017: 198-199) also writes:

But is someone really less any responsible for their actions if his or her genes are implicated? A problem with this argument is that we would be hard-pressed to find any actions that we engage in where our genes are not involved—our behaviors do not occur in any gene-free zones. Or, consider this: there actually is a particular genetic variant that, if you possess it, makes you about 40 times more likely to engage in same-sex homicides than those who possess a different variant. (66) It’s known as the Y chromosome—that is, people who possess it are biologically male. Given this, should we infer that Y chromosomes cause murders, and thus give a reduced sentence to anyone who is the carrier of such a chromosome because he is really not responsible for his actions? The philosopher Stephen Morse calls the tendency to excuse a crime because of a biological basis the “fundamental psycholegal error.” (67) The problem with this tendency is that it involves separating yout genes from yourself. Saying “my genes made me do it” doesn’t make sense because there is no “I” that is independent of your genetic makeup. But curiously, once genes are implicaed, people see, to feel that the accused is no longer fully in control of his or her actions.

Further, in the case of a child pornographer, one named Gary Cossey, the court said:

The court predicted that some fifty years from now Cossey’s offense conduct would likely be discovered to be caused by “a gene you were born with. And it’s not a gene you can get rid of.” The court expressed its belief that although Cossey was in therapy, it “can only lead, in my view, to a sincere effort on your part to control, but you can’t get rid of it. You are what you’re born with. And that’s the only explanation for what I see here.”

However, this judge punished Cossey more severely due to the ‘possibility’ that scientists may find ‘genes for’ child pornography use in 50 years. Cossey was then given another, unbiased judge, and was given a ‘more lenient’ sentence than the genetic determinist judge did.

Sean Last over at The Alternative Hypothesis is also a big believer in this so-called MAOA-race difference that explains racial differences in crime. However, as reviewed above (and as he writes), MAOA can be called the “everything but the kitchen sink gene” (Heine, 2017: 195), as I will touch on briefly below, to attribute ’causes’ to genes is not the right way to look at them. It’s not so easy to say that since one ‘has the warrior gene’ that they’d automatically be violent. Last cites a study saying that even those who have the MAOA allele who were not abused showed higher rates of violent behavior (Ficks and Waldman, 2014). They write (pg. 429):

The frequency of the ‘‘risk’’ allele in nonclinical samples of European ancestry ranges from 0.3 to 0.4, although the frequency of this allele in individuals of Asian and African ancestry appears to be substantially higher (*0.6 in both groups; Sabol et al. 1998).

So, why don’t Asians have higher rates of crime—along with blacks—if MAOA on its own causes violent and antisocial behavior? Next I know that someone would claim that “AHA! TESTOSTERONE ALSO MEDIATES THIS RELATIONSHIP!!” However, as I’ve talked about countless times (until I’m blue in the face), blacks do not have/have lower levels of testosterone than whites (Richards et al, 1992Gapstur et al, 2002; Rohrmann et al, 2007; Mazur, 2009; Lopez et al, 2013; Hu et al, 2014; Richard et al, 2014). Though young black males have higher levels of testosterone due to the environment (honor culture) (Mazur, 2016). So that canard cannot be trotted out.

All in all, these simplistic and reductionist approaches to ‘figuring out’ the ’causes’ of crime do not make any sense. To point at one gene and say that this is ‘the cause’ of that do not make sense.

One last point on ‘genes as causes’ for behavior. This is something that deserves a piece of its own, but I will just provide a quote from Eva Jablonska and Marion Lamb’s book Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life (Jablonska and Lamb, 2014: 17; read chapter one of the book here; I have the nook version so the page number may be different):

Although many psychiatrists, biochemists, and other scientists who are not geneticists (yet express themselves with remarkable facility on genetic issues) still use the language of genes as simple causal agents, and promise their audience rapid solutions to all sorts of problems, they are no more than propagandists whose knowledge or motives must be suspect. The geneticists themselves now think and talk (most of the time) in terms of genetic networks composed of tens or hundreds of genes and gene products, which interact with each other and together affect the development of a particular trait. They recognize that whether or not a trait (a sexual preference, for example) develops does not depend, in the majority of cases, on a difference in a single gene. It involves interactions among many genes, many proteins and other types of molecule, and the environment in which an individual develops.

So to say that those who have low-functioning MAOA variants have an ‘excuse’ as to why they commit crime is incorrect. I know that most people know this, but when you read some people’s writings on things like this it’s like they think that these singular genes/polymorphisms/etc cause these things on their own. In actuality, you need to look at how the whole system interacts with these things, and not reduce whole complex physiological systems to a sum of its parts. This is why implicating singular genes/polymorphisms as explanations for racial differences in crime does not make sense (as can be seen with the Japanese example).

To reduce behaviors simply to gene X and not look at the whole system does not make any sense. There are no ‘genes for’ anything, except a few Mendelian diseases (Ropers, 2010). Stating that certain genes ’cause’ X, as I have shown does not make sense and, wrongly, in my opinion, gives criminals less of a sentencing since judges find stuff like this ‘very compelling’. If that’s the case, why implicate any murderer? ‘Their genes made them do it’, right? Though, things are not that simple to implicate one gene as a cause for crime or any other complex behavior; in this sense—like for most things to do with the human body—holism makes way more sense and not reductionism. We need to look at how these genes that are ‘implicated’ in criminal behavior interact with the whole system. Only then can we understand the causes of criminal behavior. Looking at singular genes impedes us from figuring out the true underlying reasons why people commit crime.

Remember: we can’t blame “warrior genes” for violent crime. If someone does have a ‘genetic predisposition to crime’ from the MAOA gene, then wouldn’t it make more sense to give them more time? Though, the relationship is not so simple as I have covered. So to close, there is no ‘simple relationship’ between race, crime and MAOA. Not in the way that other hereditarians would like you to believe. Because if this relationship were so simple, then East Asians (Chinese, Japanese) would have the highest rates of crime, and they do not.

The ENA Theory: On Testosterone and Aggressive Behavior by Race/Ethnicity

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A commenter by the name of bbloggz alerted me to a new paper by Lee Ellis published this year titled Race/ethnicity and criminal behavior: Neurohormonal influences in which Ellis (2017) proposed his theory of ENA (evolutionary neuroandrogenic theory) and applied it to racial/ethnic differences in crime. On the face, his theory is solid and it has great explanatory power for the differences in crime rates between men and women, however, there are numerous holes in the application of the theory in regards to racial/ethnic differences in crime.

In part I, he talks about racial differences in crime. No one denies that, so on to part II.

In part II he talks about environmental causes for the racial discrepancies, that include economic racial disparities, racism and societal discrimination and subordination, a subculture of violence (I’ve been entertaining the honor culture hypothesis for a few months; Mazur (2016) drives a hard argument showing that similarly aged blacks with some college had lower levels of testosterone than blacks with less than high school education which fits the hypothesis of honor culture. Though Ellis’ ENA theory may account for this, I will address this below). However, if the environment that increases testosterone is ameliorated (i.e., honor culture environments), then there should be a subsequent decrease in testosterone and crime, although I do believe that testosterone has an extremely weak association with crime, nowhere near high enough to account for racial differences in crime, the culture of honor could explain a good amount of the crime gap between blacks and whites.

Ellis also speaks about the general stress/strain explanation, stating that blacks have higher rates of self-esteem and Asians the lowest, with that mirroring their crime rates. This could be seen as yet another case for the culture of honor in that blacks with a high self-esteem would feel the need to protect their ‘name’ or whatever the case may be and feel the need for physical altercation based on their culture.

In part III, Ellis then describes his ENA theory, which I don’t disagree with on its face as it’s a great theory with good explanatory power but there are some pretty large holes that he rightly addresses. He states that, as I have argued in the past, females selected men for higher rates of testosterone and that high rates of testosterone masculinize the brain, changing it from its ‘default feminine state’ and that the more androgens the brain is exposed to, the more likely it is for that individual to commit crime.


Ellis cites a study by Goodpaster et al (2006) in which he measured the races on the isokinetic dynamometry, pretty much a leg extension. However, one huge confound is that participants who did not return for follow-up were more likely to be black, obese and had more chronic disease (something that I have noted before in an article on racial grip strength). I really hate these study designs, but alas, it’s the best we have to go off of and there are a lot of holes in them that must be addressed. Though I applaud the researchers’ use of the DXA scan (regular readers may recall my criticisms on using calipers to assess body fat in the bench press study, which was highly flawed itself; Boyce et al, 2014) to assess body fat as it is the gold standard in the field.

Ellis (2017: 40) writes: “as brain exposure to testosterone surges at puberty, the prenatally-programmed motivation to strive for resources, status, and mating opportunities will begin to fully activate.” This is true on the face, however as I have noted the correlation between physical aggression and testosterone although positive is low at .14 (Archer, 1991; Book et al, 2001). Testosterone, as I have extensively documented, does cause social dominance and confidence which do not lead to aggression. However, when other factors are coupled with high testosterone (as noted by Mazur, 2016), high rates of crime may occur and this may explain why blacks commit crime; a mix of low IQ, high testosterone and low educational achievement making a life of crime ‘the smart way’ to live seeing as, as Ellis points out, and that intelligent individuals find legal ways to get resources while less intelligent individuals use illegal ways.

ENA theory may explain racial differences in crime

In part IV he attempts to show how his ENA theory may explain racial differences in crime—with testosterone sitting at the top of his pyramid. However, there are numerous erroneous assumptions and he does rightly point out that more research needs to be done on most of these variables and does not draw any conclusions that are not warranted based on the data he does cite. He cites one study in which testosterone levels were measured in the amniotic fluid of the fetus. The sample was 59 percent white and due to this, the researchers lumped blacks, ‘Hispanics’ and Native Americans together which showed no significant difference in prenatal testosterone levels (Martel and Roberts, 2014).

Umbilical cord and testosterone exposure

Ellis then talks about testosterone in the umbilical cord, and if the babe is exposed to higher levels of testosterone in vitro, then this should account for racial/ethnic differences in crime. However, the study he cited (Argus-Collins et al, 2012) showed no difference in testosterone in the umbilical cord while Rohrmann et al (2009) found no difference in testosterone between blacks and whites but found higher rates of SHBG (sex hormone-binding globulin) which binds to testosterone and makes it unable to leave the blood which largely makes testosterone unable to affect organ development. Thusly, if the finding of higher levels of SHBG in black babes is true, then they would be exposed to less androgenic hormones such as testosterone which, again, goes against the ENA theory.

He also cites two more studies showing that Asian babes have higher levels of umbilical cord testosterone than whites (Chinese babes were tested) (Lagiou et al, 2011; Troisi et al, 2008). This, again, goes against his theory as he rightly noted.

Circulating testosterone

Next he talks about circulating differences in testosterone between blacks and whites. He rightly notes that testosterone must be assayed in the morning within an hour after waking as that’s when levels will be highest, yet cites Ross et al (1986) where assay times were all over the place and thusly testosterone cannot be said to be higher in blacks and whites based on that study and should be discarded when talking about racial differences in testosterone due to assay time being between 10 am and 3 pm. He also cites his study on testosterone differences (Eliss and Nyborg, 1993), but, however, just as Ross et al (1986) did not have a control for WC (waist circumference) Ellis and Nyborg (1993) did not either, so just like the other study that gets cited to show that there is a racial difference in testosterone, they are pretty hugely flawed and should not be used in discussion when discussing racial differences in testosterone. Why do I not see these types of critiques for Ross et al (1986) in major papers? It troubles me…

He also seems to complain that Lopez et al (2013) controlled for physical activity (which increases testosterone) and percent body fat (which, at high levels, decreases testosterone). These variables, as I have noted, need to be controlled for. Testosterone varies and fluctuated by age; WC and BMI vary and fluctuate by age. So how does it make sense to control for one variable that has hormone levels fluctuate by age and not another? Ellis also cites studies showing that older East Asian men had higher levels of testosterone (Wu et al, 1995). Nevertheless, there is no consensus; some studies show Chinese babes have higher levels of testosterone than whites and some studies show that whites babes have higher levels of testosterone than Chinese babes. Indeed, this meta-analysis by Ethnicmuse shows that Asians have the highest levels, followed by Africans then Europeans, so this needs to be explained to save the theory that testosterone is the cause of black overrepresentation of violence (as well as what I showed that testosterone is important for vital functioning and is not the boogeyman the media makes it out to be).

Bone density and crime

Nevertheless, the next variable Ellis talks about is bone density and its relationship to crime. Some studies find that blacks are taller than whites while other show no difference. Whites are also substantially taller than Asian males. Blacks have greater bone density than the other three races, but according to Ellis, this measure has not been shown to have a relationship to crime as of yet.

Penis size, race and crime

Now on to penis size. In two articles, I have shown that there is no evidence for the assertion that blacks have larger penises than whites. However, states that penis length was associated with higher levels of testosterone in Egyptian babes. He states that self-reported penis size correlates with self-reports of violent delinquency (Ellis and Das, 2012). Ellis’ main citations for the claim that blacks have larger penises than other races comes from Nobile (1982), the Kinsey report, and Rushton and Boagert (1987) (see here for a critique of Rushton and Boagert, 1987), though he does cite a study stating that blacks had a longer penis than whites (blacks averaging 5.77 inches while whites averaged 5.53 inches). An HBDer may go “Ahah! Evidence for Rushton’s theory!”, yet they should note that the difference is not statistically significant; just because there is a small difference in one study also doesn’t mean anything for the totality of evidence on penis size and race—that there is no statistical difference!

He then cites Lynn’s (2013) paper which was based on an Internet survey and thus, self-reports are over-measured. He also cites Templer’s (2002) book Is Size Important?, which, of course, is on my list of books to read. Nevertheless, the ‘evidence’ that blacks average larger penises than whites is extremely dubious, it’s pretty conclusive that the races don’t differ in penis size. For further reading, read The Pseudoscience of Race Differences in Penis Sizeand read all of Ethnicmuses’ posts on penis size here. It’s conclusive that there is no statistical difference—if that—and any studies showing a difference are horribly flawed.

2d/4d ratio and race

Then he talks about 2d/4d ratio, which supposedly signifies higher levels of androgen exposure in vitro (Manning et al, 2008) however these results have been challenged and have not been replicated (Koehler, Simmons, and Rhodes, 2004; Yan et al, 2008, Medland et al, 2010). Even then, Ellis states that in a large analysis of 250,000 respondents, Asians had the lowest 2d/4d ratio, which if the hypothesis of in vitro hormones affecting digit length is to be believed, they have higher levels of testosterone than whites (the other samples had small ns, around 100).

Prostate-specific antigens, race, and prostate cancer

He then talks about PSA (prostate-specific antigen) rates between the races. Blacks are two times more likely to get prostate cancer, which has been blamed on testosterone. However, I’ve compiled good evidence that the difference comes down to the environment, i.e., diet. Even then, there is no evidence that testosterone causes prostate cancer as seen in two large meta-analyses (Stattin et al, 2003; Michaud, Billups, and Partin, 2015). Even then, rates of PCa (prostate cancer) are on the rise in East Asia (Kimura, 2012; Chen et al, 2015Zhu et al, 2015) which is due to the introduction of our Western diet. I will cover the increases in PCa rates in East Asia in a future article.

CAG repeats

He then reviews the evidence of CAG repeats. There is, however, no evidence that the number of CAG repeats influences sensitivity to testosterone. However, intra-racially, lower amounts of CAG repeats are associated with higher spermatozoa counts—but blacks don’t have higher levels of spermatozoa (Mendiola et al, 2011; Redmon et al, 2013). Blacks do have shorter CAG repeats, and this is consistent with the racial crime gap of blacks > whites > Asians. However, looking at the whole of the evidence, there is no good reason to assume that this has an effect on racial crime rates.

Intelligence and education

Next he talks about racial differences in intelligence and education, which have been well-established. Blacks did have higher rates of learning disabilities than whites who had higher levels of learning disabilities then Asians in a few studies, but other studies show whites and South Asians having different rates, for instance. He then talks about brain size and criminality, stating that the head size of males convicted for violent crimes did not differ from males who committed non-violent crimes (Ikaheimo et al, 2007). I won’t bore anyone with talking about what we know already: that the races differ in average brain size. However, a link between brain size and criminality—to the best of my knowledge—has yet to been discovered. IQ is implicated in crime, so I do assume that brain size is as well (no matter if the correlation is .24 or not; Pietschnig et al, 2015).

Prenatal androgen exposure

Now to wrap things up, the races don’t differ in prenatal androgen exposure, which is critical to the ENA theory; there is a small difference in the umbilical cord favoring blacks, and apparently, that predicts a high rate of crime. However, as noted, blacks have higher levels of SHBG at birth which inhibits the production of testosterone on the organs. Differences in post-pubertal testosterone are small/nonexistent and one should not talk about them when talking about differences in crime or disease acquisition such as PCa. DHT only shows a weak positive correlation with aggression—the same as testosterone (Christiansen and Winkler, 1992; however other studies show that DHT is negatively correlated with measures of physical aggression; Christiansen and Krussmann, 1987; further, DHT is not so evil after all).

Summing it all up

Blacks are not stronger than whites, indeed evidence from the races’ differing somatype, grip strength and leverages all have to do with muscular strength. Furthermore, the study that Ellis cites as ‘proof’ that blacks are stronger than whites is on one measure; an isokinetic dynamometry machine which is pretty much a leg extension. In true tests of strength, whites blow blacks away, which is seen in all major professional competitions all around the world. Blacks do have denser bones which is due to androgen production in vitro, but as of yet, there has been no research done into bone density and criminality.

The races don’t differ on penis size—and if they do it’s by tenths of an inch which is not statisitcally significant and I won’t waste my time addressing it. It seems that most HBDers will see a racial difference of .01 and say “SEE! Rushton’s Rule!” even when it’s just that, a small non-significant difference in said variable. That’s something I’ve encountered a lot in the past and it’s, frankly, a waste of time to converse about things that are not statistically significant. I’ve also rebutted the theory on 2d/4d ration as well. Finally, Asians had a similar level of androgen levels compared to blacks, with whites having the least amount. Along with a hole in the theory for racial differences in androgen causing crime, it’s yet another hole in the theory for racial differences in androgens causing racial differences in penis size and prostate cancer.

On intelligence scores, no one denies that blacks have scored about 1 SD lower than whites for 100 years, no one denies that blacks have a lower educational attainment. In regards to learning disabilities, blacks seem to have the highest rates, followed by Native Americans, than non-Hispanic whites, East Asians and the lowest rates found in South Asians. He states only one study links brain size to criminal behavior and it showed a significant inverse relationship with crime but not other types of offenses.

This is a really good article and I like the theory, but it’s full of huge holes. Most of the variables described by Ellis have been shown to not vary at all or much between the races (re: penis size, testosterone, strength [whites are stronger] prostate cancer caused mainly by diet, 2d/4d ratio [no evidence of it showing a digit ratio difference], and bone density not being studied). Nevertheless, a few of his statements do await testing so I await future studies on the matter. He says that androgen exposure ‘differs by race and ethnicity’, yet the totality of evidence shows ‘not really’ so that cannot be the cause of higher amounts of crime. Ellis talks about a lot of correlates with testosterone, but they do not pass the smell test. Most of it has been rebutted. In fact, one of the central tenets of the ENA theory is that the races should differ in 2d/4d ratio due to exposure of differing levels of the hormone in vitro. Alas, the evidence to date has not shown this—it has in fact shown the opposite.

ENA theory is good in thought, but it really leaves a lot to be desired in regards to explaining racial differences in crime. More research needs to be looked into in regards to intelligence and education and its effect on crime. We can say that low IQ people are more likely to drop out of school and that is why education is related to crime. However, in Mazur (2016) shows that blacks matched for age had lower levels of testosterone if they had some college under their belt. This seems to point in the direction of the ENA theory, however then all of the above problems with the theory still need to be explained away—and they can’t! Furthermore, one of the nails in the coffin should be this: East Asian males are found to have higher levels of testosterone than white males, often enough, and East Asian males actually have the lowest rate of crime in the worle!

This seems to point in the direction of the ENA theory, however then all of the above problems with the theory still need to be explained away—and they can’t! Furthermore, one of the nails in the coffin should be this: East Asian males are found to have higher levels of testosterone than white males, often enough, and East Asian males actually have some of the lowest rate of crime in the world (Rushton, 1995)! So this is something that needs to be explained if it is to be shown that testosterone facilitates aggression and therefore, crime.


I’ve shown—extensively—that there is a low positive correlation between testosterone and physical aggression, why testosterone does not cause crime, and have definitively shown that, by showing how flawed the other studies are that purport to show blacks have higher testosterone levels than whites, along with citing large-scale meta-analyses, that whites and blacks either do not differ or the differences is small to explain any so-called differences in disease acquisition or crime. One final statement on the CAG repeats, they are effect by obesity, men who had shorter CAG repeats were more likely to be overweight, which would skew readings (Gustafsen, Wen, and Koppanati, 2003). So depending on the study—and in most of the studies I cite whites have a higher BMI than blacks—BMI and WC should be controlled for due to the depression of testosterone.

It’s pretty conclusive that testosterone itself does not cause crime. Most of the examples cited by Ellis have been definitively refuted, and his other claims lack evidence at the moment. Even then, his theory rests on the 2d/4d ratio and how blacks may have a lower 2d/4d ratio than whites. However, I’ve shown that there is no significant relationship between 2d/4d ratio and traits mediated by testosterone (Kohler, Simmons, and Rhodes, 2004) so that should be enough to put the theory to bed for good.

Race, Testosterone, and Prostate Cancer

1900 words

I have explicitly shown how the ‘black men have more T’ canard is false. I have provided sufficient evidence for this claim. People claim to be unbiased—like PumpkinPerson—and say they’re only ‘looking for the truth’. However, it’s clear that in all of my conversations with him on the matter, he’s reaching for anything that affirms his worldview when he is shown evidence to the contrary of his beliefs (Nyhan and Reifler, 2012). It’s so very easy to notice this. I will provide yet more robust data on the black/white testosterone ‘gap’ while also critiquing some other studies that didn’t control for some pretty important variables. The gist is: after controlling for the most important variables, (waist circumference, BMI) the ‘testosterone difference’ all but disappears—and I don’t think people will argue for .0068 ng/ml higher testosterone cause things like prostate cancer and higher rates of crime.

Gapstur et al (2002) studied 5,115 individuals from aged 18-30 who completed baseline examinations at one of four locations from 1985-86: Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California. Then, 4 follow-ups were completed (Year 2: 1987-88; year 5: 1990-91; year 7: 1992-93; and year 10: 1995-96).

The number of blacks who completed the baseline information was 1157 whereas for whites it was 1171. They measured waist circumference (WC) at the minimal abdominal girth. Whether or not one took medication was self-reported, so Gapstur et al (2002) separated medications into two categories: regulation or interfering with binding likely, or interfering with binding unlikely/impossible.

Now, before I discuss the results of Gapstur et al (2002) I must talk about why they controlled for BMI (body mass index) and WC along with age. Since the obesity rate differs by race/ethnicity, along with obesity frequently changing with age, all three of the variables need to be controlled for to get a clearer picture of what circulating testosterone looks like—on average—between blacks and whites. White men are slightly more likely than black men to be obese/overweight in America (being African-American seems to be a protector against obesity; African American men with more African ancestry are less likely to be obese), however the sample used by Gapstur et al (2002) had blacks who had a higher WC and BMI than whites.

At year 2, there was no significant difference in total serum testosterone between the races with or without adjustment for age, BMI and WC. The only part in this analysis that blacks had higher testosterone levels than whites was at year ten, with black ‘enjoying’ .0063 ng/ml higher levels than whites. Furthermore, there was no significant difference in testosterone between blacks and whites after adjustment for age. Only adjusting for BMI, blacks had substantially higher levels of testosterone (.21 ng/ml) however after including WC and the changes in WC between blacks and whites (blacks had a greater change over the study) this difference all but disappeared. The age-associated changes in testosterone between blacks and whites were similar after adjusting for waist circumference and BMI. Also, after adjusting for the relevant confounds, free testosterone did not differ between blacks and whites.

Measures of body size (i.e., BMI and WC) must be controlled for when comparing race/ethny since levels of obesity vary amongst them as well as obesity constantly changing with age. Furthermore, testosterone increased for both groups between the ages of 20-21 to 22-23 (blacks had a higher T level by .7 ng/ml at age 20-21), with the two groups diverging at age 22-23 with blacks having higher levels of total testosterone by .1 ng/ml.

The average ages for the cohort were 28.4 and 28.8 for blacks and whites respectfully. Thus, blacks (theoretically) had a slight advantage due to the age confound, which had to be controlled for. The unadjusted mean total testosterone, SHGB, and free testosterone were not statistically significant at any point in the study except at year 10 where blacks had slightly higher levels at 5.8 ng/ml compared to whites’ 5.69 ng/ml. The difference in year 2 (when testosterone levels raised for both groups) was a difference of 5.8 and 5.75 for blacks and whites respectfully. Free testosterone did not differ at all from years 2, 7, and 10 (.17 compared to .17 in year 2; .16 to .15 in year 7; and .16 to .15 in year 10; blacks and whites respectfully).

Levels of testosterone were also found to be lower in 12-13-year-old blacks compared to whites (Lopez et al, 2013). In this study, Mexican Americans had higher T levels, while after adjustments for confounds, blacks and whites did not differ. They conclude that testosterone levels were not higher in black compared to white adolescents. Black men have higher levels of estradiol than white men, not testosterone (Roerrmann et al, 2007; Lopez et al, 2013). These studies are done to see the relationship between PCa (prostate cancer) and certain hormones. These and other studies have shown that the black-white difference isn’t large (Richard et al, 1992; Roerrmann et al, 2007; Lopez et al, 2013; Richard et al, 2014) and that prostate cancer is not caused by abnormally high testosterone levels (Stattin et al, 2003; Michaud, Billups, and Partins, 2015).

Ross et al (1986) did not have a measure of central adiposity (WC), thusly the results were confounded. Further, the other study Rushton cited in Race, Evolution, and Behavior is and Nyborg (1992) on discharged army veterans stating a difference of 3 percent, Ellis and Nyborg did not control for WC nor BMI. As seen in the Gapstur et al (2002) study, WC is an extremely important variable to control for as decreases in testosterone are high when central adiposity is high (Wang et al, 2011) so if we are trying to compare two ethnies on one variable such as testosterone, all of the above variables MUST be controlled for, and if they are not then they can be safely disregarded.

The non-inclusion of a measure of WC is the most likely cause of the different results found in Gapstur et al (2002). If you don’t control for WC, then you cannot get an actual and reliable testosterone reading since the results will be confounded. Anyone who says otherwise that the aforementioned variables do not need to be controlled for literally have no idea what they’re talking about.

Lastly, a few more things must be addressed. In PumpkinPerson’s most recent article “Racial differences in testosterone“, he seems to now disavow testosterone as a useful measure since it can fluctuate due to winning sports games, to marriage, to anticipating confrontation, to being in a relationship, to honor culture. Now his thing is exposure to androgens (testosterone) in the womb. Supposedly, blacks have the lowest digit ratio, and low digit ratios signify higher levels of testosterone in vitro (Manning et al, 2004). However, the relationship is far from proven (Koehler, Simmons, and Rhodes, 2004; Yan et al, 2008, Medland et al, 2010) with these results, leaning towards no. Koheler, Simmons, and Rhodes (2004) failed to find any significant correlation between 2d/4d ratio and traits mediated by testosterone. So this is another claim that’s been put to bed as well.

There is a lot of bullshit to sift through out there; some things may seem simple at face value, but if you dig into it, it’s much more likely to be more complex than what it looks to be on the surface. This one singular variable (testosterone) is one of them. It does not differ between the races; exposure to androgens in the womb doesn’t affect digit ratio; high testosterone does not cause prostate cancer, but low testosterone does (Morgentaler, Brunning, and DeWolf, 1996) ; you can literally inject exogenous testosterone into a man with PCa and not effect this malady (Eisenberg, 2015; Boyle et al, 2016)

I hope this is the last time I have to say this: testosterone does not differ between blacks and whites. Testosterone is not the cause of differences in mortality rate in regards to PCa. (Diet is the much more likely factor) People still regurgitate Rushton’s bullshit from REB; Ross et al (1986) still gets cited to this day, when there are much more robust studies and samples that controlled for the relevant confounds that Ross et al (1986) did not control for. This is why that study is garbage and should not be looked at when assessing testosterone differences between the races. Much larger and robust samples show that there is no testosterone difference when the WC is controlled for.

Testosterone is not higher in black Americans; the data shows either an extremely negligible difference or no difference, not the huge 13 and 21 percent difference in free and total testosterone in black Americans in Ross et al (1986).

For the last time, and say it with me: testosterone does NOT differ by race, 2d:4d ratio is NOT influenced by androgens in vitro, and testosterone does NOT influence PCa rates. Testosterone is an extremely important hormone for vital functioning, so whoever believes the myths of the high testosterone savage and LIKES having low testosterone, have fun with a slew of maladies later in life.


Boyle, P., Koechlin, A., Bota, M., Donofrio, A., Zaridze, D. G., Perrin, P., . . . Boniol, M. (2016). Endogenous and exogenous testosterone and the risk of prostate cancer and increased prostate-specific antigen (PSA) level: a meta-analysis. BJU International,118(5), 731-741. doi:10.1111/bju.13417

Dobs, A., & Morgentaler, A. (2008). Does Testosterone Therapy Increase the Risk of Prostate Cancer? Endocrine Practice,14(7), 904-911. doi:10.4158/ep.14.7.904

Eisenberg, M. L. (2015). Testosterone Replacement Therapy and Prostate Cancer Incidence. The World Journal of Men’s Health, 33(3), 125–129.

Gapstur, S. M., Kopp, P., Gann, P. H., Chiu, B. C., Colangelo, L. A., & Liu, K. (2006). Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study. International Journal of Obesity. doi:10.1038/sj.ijo.0803465

Koehler, N., Simmons, L. W., & Rhodes, G. (2004). How well does second-to-fourth-digit ratio in hands correlate with other indications of masculinity in males? Proceedings of the Royal Society B: Biological Sciences,271(Suppl_5). doi:10.1098/rsbl.2004.0163

Lopez, D. S., Peskoe, S. B., Joshu, C. E., Dobs, A., Feinleib, M., Kanarek, N., . . . Platz, E. A. (2013). Racial/ethnic differences in serum sex steroid hormone concentrations in US adolescent males. Cancer Causes & Control,24(4), 817-826. doi:10.1007/s10552-013-0154-8

Michaud, J. E., Billups, K. L., & Partin, A. W. (2015). Testosterone and prostate cancer: an evidence-based review of pathogenesis and oncologic risk. Therapeutic Advances in Urology,7(6), 378-387. doi:10.1177/1756287215597633

Medland, S. E., Zayats, T., Glaser, B., Nyholt, D. R., Gordon, S. D., Wright, M. J., . . . Evans, D. M. (2010). A Variant in LIN28B Is Associated with 2D:4D Finger-Length Ratio, a Putative Retrospective Biomarker of Prenatal Testosterone Exposure. The American Journal of Human Genetics,86(4), 519-525. doi:10.1016/j.ajhg.2010.02.017

Manning, J., Stewart, A., Bundred, P., & Trivers, R. (2004). Sex and ethnic differences in 2nd to 4th digit ratio of children. Early Human Development,80(2), 161-168. doi:10.1016/j.earlhumdev.2004.06.004

Morgentaler, A., Brunning, C. O., 3rd, & DeWolf, W. C. (1996). Occult Prostate Cancer in Men With Low Serum Testosterone Levels. JAMA: The Journal of the American Medical Association,276(23), 1904. doi:10.1001/jama.1996.03540230054035

Nyhan, B., & Reifler, J. (2010). When Corrections Fail: The Persistence of Political Misperceptions. Political Behavior,32(2), 303-330. doi:10.1007/s11109-010-9112-2

Richard, A., Rohrmann, S., Zhang, L., Eichholzer, M., Basaria, S., Selvin, E., . . . Platz, E. A. (2014). Racial variation in sex steroid hormone concentration in black and white men: a meta-analysis. Andrology,2(3), 428-435. doi:10.1111/j.2047-2927.2014.00206.x

Rohrmann, S., Nelson, W. G., Rifai, N., Brown, T. R., Dobs, A., Kanarek, N., . . . Platz, E. A. (2007). Serum Estrogen, But Not Testosterone, Levels Differ between Black and White Men in a Nationally Representative Sample of Americans. The Journal of Clinical Endocrinology & Metabolism,92(7), 2519-2525. doi:10.1210/jc.2007-0028

Wang, C., Jackson, G., Jones, T. H., Matsumoto, A. M., Nehra, A., Perelman, M. A., … Cunningham, G. (2011). Low Testosterone Associated With Obesity and the Metabolic Syndrome Contributes to Sexual Dysfunction and Cardiovascular Disease Risk in Men With Type 2 Diabetes. Diabetes Care, 34(7), 1669–1675.

Yan RHY, Malisch JL, Hannon RM, Hurd PL, Garland T Jr (2008) Selective Breeding for a Behavioral Trait Changes Digit Ratio. PLoS ONE 3(9): e3216.

Race, Testosterone, and Honor Culture

2300 words

Misinformation about testosterone and strength in regards to race is rampant in the HBD-o-sphere. One of the most oft-repeated phrases is that “Blacks have higher levels of testosterone than whites”, even after controlling for numerous confounds. However, the people who believe this literally only cite one singular study with 50 blacks and 50 whites. Looking at more robust data with higher ns shows a completely different story. Tonight I will, again, go through the race/testosterone conundrum (again).

Type I fibers fire first when heavy lifting. Whites have more type I fibers. Powerlifters and Olympic lifters have a greater amount type IIa fibers, with fewer type IIx fibers (like whites). This explains why blacks are hardly represented in powerlifting and strongman competitions.

Somatype, too, also plays a role. Whites are more endo than blacks who are more meso. Endomorphic individuals are stronger, on average, than mesomorphic and ectomorphic individuals.

Blacks have narrower hips and pelves. This morphological trait further explains why blacks dominate sports. Some people may attempt to pick out one variable that I speak about (fiber type, morphology, somatype, fat mass, etc) and attempt to disprove it, thinking that disproving that variable will discredit my whole argument. However, fiber typing is set by the second trimester, with no change in fiber type from age 6 to adulthood (Bell et al, 1980).

It is commonly believed that blacks have higher levels of testosterone than whites. However, this claim is literally based off of one study (Ross et al, 1986) when other studies have shown low to no difference in T levels (Richards et al, 1992; Gapstur et al, 2002; Rohrmann et al, 2007; Mazur, 2009; Lopez et al, 2013; Richard et al 2014). People who still push the “blacks-have-higher-T-card” in the face of this evidence are, clearly, ideologues who want to cushion their beliefs when presented with contradictory evidence (Nyhan and Reifler, 2010).

‘Honor Culture’ and testosterone

In all of my articles on this subject, I have stated—extensively—that testosterone is mediated by the environment. That is, certain social situations can increase testosterone. This is a viewpoint that I’ve emphatically stated. I came across a paper while back that talks about a sociological perspective (I have huge problems with social ‘science’, [more on that soon] but this study was very well done) in regards to the testosterone difference between blacks and whites.

Some people when they read this, however, may go immediately to the part of the paper that says what they want it to say without fully assessing the paper. In this section, I will explain the paper and how it confirms my assertions/arguments.

Mazur (2016) begins the paper talking about ‘honor culture‘, which is a culture where people avoid intentionally offending others while also maintaining a status for not backing down from a confrontation. This theory was proposed by Richard Nisbett in 1993 to explain why the South had higher rates of violence—particularly the Scotch-Irish.

However parsimonious the theory may sound, despite its outstanding explanatory power, it doesn’t hold while analyzing white male homicides in the South. It also doesn’t hold analyzing within-county homicide rates either, since apparently poverty better explains higher homicide rates.

But let’s assume it’s true for blacks. Let’s assume the contention to be true that there is an ‘honor culture’ that people take part in.

Young black men with no education had higher levels of testosterone than educated whites and blacks. Looking at this at face value—literally going right to the section of the paper that says that poor blacks had higher testosterone, nearly 100 ng/ml higher than the mean testosterone of whites. As Mazur (2016) notes, this contradicts his earlier 2009 study in which he found no difference in testosterone between the races.


Note the low testosterone for both races at age 20-29—ranging from about 515 to 425—why such low testosterone levels for young men? Anyway, the cause for the higher levels is due to the type of honor culture that blacks participate in, according to Mazur (which is consistent with the data showing that testosterone rises during conflict/aggressive situations).

Mazur cites Elijah Anderson, saying that most youths have a “code of the streets” they take part in, which have to do with interpersonal communication such as “gait and verbal expressions” to deter aggressive behavior.

Testosterone is not a causal variable in regards to violent behavior. But it does rise during conflicts with others, watching a favorite sports team, asserting dominance, and even how you carry yourself (especially your posture). Since low-class blacks participate in these types of behaviors, then they would have higher levels of testosterone due to needing to “keep their status.”

When testosterone rises in these situations, it increases the response threat in mens’ brains, most notably showing increased activity in the amygdala. Further, dominant behavior and posture also increase testosterone levels. Putting this all together, since blacks with only a high school education have higher testosterone levels and are more likely to participate in honor culture compared to whites and blacks with higher educational achievement, then they would have higher testosterone levels than whites and blacks with a high school education who do not participate in honor culture.

Further, as contrary to what I have written in the past (and have since rescinded), there is no indication of higher testosterone levels in black women with low education. It seems this ‘honor culture’ effect on testosterone only holds for black men with only a high school education.

Mazur’s (2016) most significant finding was that black men aged 20-29 with only a high school education had 91 ng/ml higher testosterone than whites. Among older and/or educated men, testosterone did not vary. This indicates that since they have attained higher levels of educational success, there is no need to participate in ‘honor culture’.

This is yet further evidence for my assertion that environmental variables such as posture, dominance, and aggressive behavior raise testosterone levels.

The honor culture hypothesis is found to hold in Brazil in a comparative study of 160 inmates and non-inmates (De Souza et al, 2016). As Mazur (2016) notes, the honor culture hypothesis could explain the high murder rate for black Americans—the need to ‘keep their status’. It’s important to note that this increase in testosterone was not noticed in teenage or female blacks (because they don’t participate in honor culture).

There is a perfectly good environmental—not genetic—reason for this increase in testosterone in young blacks with only a high school education. Now that we know this, back to race and strength.

Mazur (2009) found that black men in the age range of 20-69, they averaged .39 ng/ml higher testosterone than whites, which is partly explained by lower marriage rates and low adiposity. White men are more likely to be obese than black men, since black men with more African ancestry are less likely to be obese. When controlling for BMI, blacks are found to have 2.5-4.9 percent more testosterone than whites (Gapstur et al, 2002, Rohrmann et al, 2007, Richard et al, 2014). There is little evidence for the assertion that blacks have higher levels of testosterone without environmental triggers.

Blacks between the age of 12 and 15 average lower levels of testosterone than whites. However, after the age of 15, “testosterone levels increase rapidly” with blacks having higher peak levels than whites (seen in table 2 below). After adjusting for the usual confounds (BMI, smoking, age, physical activity, and waist circumference), blacks still had higher levels of testosterone—which is attributed to higher levels of lean mass.


As seen above in table 2 from Hu et al (2014), the difference in total testosterone between blacks and whites aged 20-39 was 6.29 ng/ml and 5.04 ng/ml respectively, with free testosterone for whites being 11.50 and 13.56 for blacks and finally bioavailable testosterone for whites and blacks aged 20-39 was 281.23 and 327.18 ng/ml respectively. These small differences in testosterone cannot account for racial disparities in violence nor prostate cancer—since there is no relationship between prostate cancer and testosterone (Stattin et al, 2003; Michaud, Billups, and Partin, 2015).

In regards to Africans, the best studies I can find comparing some African countries with the West study salivary testosterone. However, there is a direct correlation between salivary testosterone and free serum testosterone (Wang et al, 1981; Johnson, Joplin, and Burrin, 1987). Of the studies I could find, Kenyan pastoralists called the Ariaal have lower levels of testosterone than Western men (Campbell, O’Rourke, and Lipson, 2003; Campbell, Gray, and Ellison, 2006) while men in Zimbabwe had levels “much lower” compared to Western populations (Lukas, Campbell, and Ellison, 2004). Lastly, among men aged 15 to 30, salivary testosterone levels in an American sample was 335 pmol//l compared to 286 pmol/l in men from the Congo (Elisson et al, 2002). Even certain African populations don’t have higher testosterone levels than Western peoples.


The meme that blacks have higher rates of testosterone in comparison to whites needs to be put to rest. This is only seen in blacks who participate in ‘honor culture’, which is an environmental variable. This is in contrast to people who believe that it is genetic in nature—environmental variables can and do drive hormones. Mazur (2016) is proof of that. Mazur (2016) also shows that the honor culture hypothesis doesn’t hold for teens or black males—so they don’t have elevated levels of testosterone. Certain studies of African populations, however, do not show higher levels of testosterone than Western populations.

Looking at the complete literature—rather than a select few studies— we can see that testosterone levels between white and black Americans are not as high as is commonly stated (Richards et al, 1992; Gapstur et al, 2002; Rohrmann et al, 2007; Mazur, 2009; Lopez et al, 2013; Hu et al, 2014; Richard et al, 2014). Further, even if blacks did have higher levels of testosterone than whites—across the board (sans honor culture), it still wouldn’t explain higher rates of black violence when compared to whites, nor would it explain higher prostate cancer rates (Stattin et al, 2003; Michaud, Billups, and Partin, 2015).

Only blacks with low educational achievement have higher levels of testosterone—which, even then is not enough to explain higher rates of violence or prostate cancer acquisition. Other factors explain the higher murder rate (i.e., honor culture, which increases testosterone, the environmental trigger matters first and foremost) and violent crime that blacks commit. But attempting to explain it with 30-year-old studies (Ross et al, 1986) and studies that show that environmental factors increase testosterone (Mazur, 2016) don’t lend credence to that hypothesis.


Bell, R. D., Macdougall, J. D., Billeter, R., & Howald, H. (1980). Muscle fiber types and morphometric analysis of skeletal muscle in six-year-old children. Medicine & Science in Sports & Exercise,12(1). doi:10.1249/00005768-198021000-00007

Campbell, B., O’rourke, M. T., & Lipson, S. F. (2003). Salivary testosterone and body composition among Ariaal males. American Journal of Human Biology,15(5), 697-708. doi:10.1002/ajhb.10203

Campbell, B. C., Gray, P. B., & Ellison, P. T. (2006). Age-related patterns of body composition and salivary testosterone among Ariaal men of Northern Kenya. Aging Clinical and Experimental Research,18(6), 470-476. doi:10.1007/bf03324846

De Souza, Souza, B. C., Bilsky, W., & Roazzi, A. (2016). The culture of honor as the best explanation for the high rates of criminal homicide in Pernambuco: A comparative study with 160 convicts and non-convicts. Anuario de Psicología Jurídica,26(1), 114-121. doi:10.1016/j.apj.2015.03.001

Ellison, P. T., Bribiescas, R. G., Bentley, G. R., Campbell, B. C., Lipson, S. F., Panter-Brick, C., & Hill, K. (2002). Population variation in age-related decline in male salivary testosterone. Human Reproduction,17(12), 3251-3253. doi:10.1093/humrep/17.12.3251

Gapstur SM, Gann PH, Kopp P, Colangelo L, Longcope C, Liu K. Serum androgen concentrations in young men: a longitudinal analysis of associations with age, obesity, and race—the CARDIA male hormone study. Cancer Epidemiol Biomarkers Prev 2002; 11: 10417

Hu, H., Odedina, F. T., Reams, R. R., Lissaker, C. T., & Xu, X. (2014). Racial Differences in Age-Related Variations of Testosterone Levels Among US Males: Potential Implications for Prostate Cancer and Personalized Medication. Journal of Racial and Ethnic Health Disparities,2(1), 69-76. doi:10.1007/s40615-014-0049-8

Johnson, S. G., Joplin, G. F., & Burrin, J. M. (1987). Direct assay for testosterone in saliva: Relationship with a direct serum free testosterone assay. Clinica Chimica Acta,163(3), 309-318. doi:10.1016/0009-8981(87)90249-x

Lopez, D. S., Peskoe, S. B., Joshu, C. E., Dobs, A., Feinleib, M., Kanarek, N., . . . Platz, E. A. (2013). Racial/ethnic differences in serum sex steroid hormone concentrations in US adolescent males. Cancer Causes & Control,24(4), 817-826. doi:10.1007/s10552-013-0154-8

Lukas, W. D., Campbell, B. C., & Ellison, P. T. (2004). Testosterone, aging, and body composition in men from Harare, Zimbabwe. American Journal of Human Biology,16(6), 704-712. doi:10.1002/ajhb.20083

Mazur, A. (2009). The age-testosterone relationship in black, white, and Mexican-American men, and reasons for ethnic differences. The Aging Male,12(2-3), 66-76. doi:10.1080/13685530903071802

Mazur, A. (2016). Testosterone Is High among Young Black Men with Little Education. Frontiers in Sociology,1. doi:10.3389/fsoc.2016.00001

Michaud, J. E., Billups, K. L., & Partin, A. W. (2015). Testosterone and prostate cancer: an evidence-based review of pathogenesis and oncologic risk. Therapeutic Advances in Urology,7(6), 378-387. doi:10.1177/1756287215597633

Nyhan, B., & Reifler, J. (2010). When Corrections Fail: The Persistence of Political Misperceptions. Political Behavior,32(2), 303-330. doi:10.1007/s11109-010-9112-2

Richard, A., Rohrmann, S., Zhang, L., Eichholzer, M., Basaria, S., Selvin, E., . . . Platz, E. A. (2014). Racial variation in sex steroid hormone concentration in black and white men: a meta-analysis. Andrology,2(3), 428-435. doi:10.1111/j.2047-2927.2014.00206.x

Richards, R. J., Svec, F., Bao, W., Srinivasan, S. R., & Berenson, G. S. (1992). Steroid hormones during puberty: racial (black-white) differences in androstenedione and estradiol–the Bogalusa Heart Study. The Journal of Clinical Endocrinology & Metabolism,75(2), 624-631. doi:10.1210/jcem.75.2.1639961

Rohrmann, S., Nelson, W. G., Rifai, N., Brown, T. R., Dobs, A., Kanarek, N., . . . Platz, E. A. (2007). Serum Estrogen, But Not Testosterone, Levels Differ between Black and White Men in a Nationally Representative Sample of Americans. The Journal of Clinical Endocrinology & Metabolism,92(7), 2519-2525. doi:10.1210/jc.2007-0028

Ross R, Bernstein L, Judd H, Hanisch R, Pike M, Henderson B. Serum testosterone levels in healthy young black and white men. J Natl Cancer Inst. 1986 Jan;76(1):45–48

Stattin, P., Lumme, S., Tenkanen, L., Alfthan, H., Jellum, E., Hallmans, G., . . . Hakama, M. (2003). High levels of circulating testosterone are not associated with increased prostate cancer risk: A pooled prospective study. International Journal of Cancer,108(3), 418-424. doi:10.1002/ijc.11572

Wang, C., Plymate, S., Nieschlag, E., & Paulsen, C. A. (1981). Salivary Testosterone in Men: Further Evidence of a Direct Correlation with Free Serum Testosterone. The Journal of Clinical Endocrinology & Metabolism,53(5), 1021-1024. doi:10.1210/jcem-53-5-1021

Black-White Differences in Muscle Fiber and Its Role In Disease and Obesity

1700 words

How do whites and blacks differ by muscle fiber and what does it mean for certain health outcomes? This is something I’ve touched on in the past, albeit briefly, and decided to go in depth on it today. The characteristics of skeletal muscle fibers dictate whether one has a higher or lower chance of being affected by cardiometabolic disease/cancer. Those with more type I fibers have less of a chance of acquiring diabetes while those with type II fibers have a higher chance of acquiring debilitating diseases. This has direct implications for health disparities between the two races.

Muscle fiber typing by race

Racial differences in muscle fiber typing explain differences in strength and mortality. I have, without a shadow of a doubt, proven this. So since blacks have higher rates of type II fibers while whites have higher rates of type I fibers (41 percent type I for white Americans, 33 percent type I for black Americans, Ama et al, 1985) while West Africans have 75 percent fast twitch and East Africans have 25 percent fast twitch (Hobchachka, 1988). Further, East and West Africans differ in typing composition, 75 percent fast for WAs and 25 percent fast for EAs, which has to do with what type of environment they evolved in (Hochhachka, 1998). What Hochhachka (1998) also shows is that high latitude populations (Quechua, Aymara, Sherpa, Tibetan and Kenyan) “show numerous similarities in physiological hypoxia defence mechanisms.” Clearly, slow-twitch fibers co-evolved here.

Clearly, slow-twitch fibers co-evolved with hypoxia. Since hypoxia is the deficiency in the amount of oxygen that reaches the tissues, populations in higher elevations will evolve hypoxia defense mechanisms, and with it, the ability to use the oxygen they do get more efficiently. This plays a critical role in the fiber typing of these populations. Since they can use oxygen more efficiently, they then can become more efficient runners. Of course, these populations have evolved to be great distance runners and their morphology followed suit.

Caesar and Henry (2015) also show that whites have more type I fibers than blacks who have more type II fibers. When coupled with physical inactivity, this causes higher rates of cancer and cardiometabolic disease. Indeed, blacks have higher rates of cancer and mortality than whites (American Cancer Society, 2016), both of which are due, in part, to muscle fiber typing. This could explain a lot of the variation in disease acquisition in America between blacks and whites. Physiologic differences between the races clearly need to be better studied. But we first must acknowledge physical differences between the races.

Disease and muscle fiber typing

Now that we know the distribution of fiber types by race, we need to see what type of evidence there is that differing muscle fiber typing causes differences in disease acquisition.

Those with fast twitch fibers are more likely to acquire type II diabetes and COPD (Hagiwara, 2013); cardiometabolic disease and cancer (Caesar and Henry, 2015); a higher risk of cardiovascular events (Andersen et al, 2015, Hernelahti et al, 2006); high blood pressure, high heart rate, and unfavorable left ventricle geometry leading to higher heart disease rates and obesity (Karjalainen et al, 2006) etc. Knowing what we know about muscle fiber typing and its role in disease, it makes sense that we should take this knowledge and acknowledge physical racial differences. However, once that is done then we would need to acknowledge more uncomfortable truths, such as the black-white IQ gap.

One hypothesis for why fast twitch fibers are correlated with higher disease acquisition is as follows: fast twitch fibers fire faster, so due to mechanical stress from rapid and forceful contraction, this leads the fibers to be more susceptible to damage and thus the individual will have higher rates of disease. Once this simple physiologic fact is acknowledged by the general public, better measures can be taken for disease prevention.

Due to differences in fiber typing, both whites and blacks must do differing types of cardio to stay healthy. Due to whites’ abundance of slow twitch fibers, aerobic training is best (not too intense). However, on the other hand, due to blacks’ abundance of fast twitch fibers, they should do more anaerobic type exercises to attempt to mitigate the diseases that they are more susceptible due to their fiber typing.

Black men with more type II fibers and less type I fibers are more likely to be obese than ‘Caucasian‘ men are to be obese (Tanner et al, 2001). More amazingly, Tanner et al showed that there was a positive correlation (.72) between weight loss and percentage of type I fibers in obese patients. This has important implications for African-American obesity rates, as they are the most obese ethny in America (Ogden et al, 2016) and have higher rates of metabolic syndrome (a lot of the variation in obesity does come down food insecurity, however). Leaner subjects had higher proportions of type I fibers compared to type II. Blacks have a lower amount of type I fibers compared to whites without adiposity even being taken into account. Not surprisingly, when the amount of type I fibers was compared by ethnicity, there was a “significant interaction” with ethnicity and obesity status when type I fibers were compared (Tanner et al, 2001). Since we know that blacks have a lower amount of type I fibers, they are more likely to be obese.

In Tanner et al’s sample, both lean blacks and whites had a similar amount of type I fibers, whereas the lean blacks possessed more type I fibers than the obese black sample. Just like there was a “significant interaction” between ethnicity, obesity, and type I fibers, the same was found for type IIb fibers (which, as I’ve covered, black Americans have more of these fibers). There was, again, no difference between lean black and whites in terms of type I fibers. However, there was a difference in type IIb fibers when obese blacks and lean blacks were compared, with obese blacks having more IIb fibers. Obese whites also had more type IIb fibers than lean whites. Put simply (and I know people here don’t want to hear this), it is easier for people with type I fibers to lose weight than those with type II fibers. This data is some of the best out there showing the relationship between muscle fiber typing and obesity—and it also has great explanatory power for black American obesity rates.


Muscle fiber differences between blacks and whites explain disease acquisition rates, mortality rates (Araujo et al, 2010), and differences in elite sporting competition between the races. I’ve proven that whites are stronger than blacks based on the available scientific data/strength competitions (click here for an in-depth discussion). One of the most surprising things that muscle fibers dictate is weight loss/obesity acquisition. Clearly, we need to acknowledge these differences and have differing physical activity protocols for each racial group based on their muscle fiber typing. However, I can’t help but think about the correlation between strength and mortality now. This obesity/fiber type study puts it into a whole new perspective. Those with type I fibers are more likely to be physically stronger, which is a cardioprotectant, which then protects against all-cause mortality in men (Ruiz et al, 2008; Volaklis, Halle, and Meisenger, 2015). So the fact that black Americans have a lower life expectancy as well as lower physical strength and more tpe II fibers than type I fibers shows why blacks are more obese, why blacks are not represented in strength competitions, and why blacks have higher rates of disease than other populations.The study by Tanner et al (2001) shows that there obese people are more likely to have type II fibers, no matter the race. Since we know that blacks have more type II fibers on average, this explains a part of the variance in the black American obesity rates and further disease acquisition/mortality.

The study by Tanner et al (2001) shows that there obese people are more likely to have type II fibers, no matter the race. Since we know that blacks have more type II fibers on average, this explains a part of the variance in the black American obesity rates and further disease acquisition/mortality.

Differences in muscle fiber typing do not explain all of the variance in disease acquisition/strength differences, however, understanding what the differing fiber typings do, metabolically speaking, along with how they affect disease acquisition will only lead to higher qualities of life for everyone involved.


Araujo, A. B., Chiu, G. R., Kupelian, V., Hall, S. A., Williams, R. E., Clark, R. V., & Mckinlay, J. B. (2010). Lean mass, muscle strength, and physical function in a diverse population of men: a population-based cross-sectional study. BMC Public Health,10(1). doi:10.1186/1471-2458-10-508

Andersen K, Lind L, Ingelsson E, Amlov J, Byberg L, Miachelsson K, Sundstrom J. Skeletal muscle morphology and risk of cardiovascular disease in elderly men. Eur J Prev Cardiol 2013.

Ama PFM, Simoneau JA, Boulay MR, Serresse Q Thériault G, Bouchard C. Skeletal muscle characteristics in sedentary Black and Caucasian males. J Appl Physiol 1986: 6l:1758-1761.

American Cancer Society. Cancer Facts & Figures for African Americans 2016-2018. Atlanta: American Cancer Society, 2016.

Ceaser, T., & Hunter, G. (2015). Black and White Race Differences in Aerobic Capacity, Muscle Fiber Type, and Their Influence on Metabolic Processes. Sports Medicine,45(5), 615-623. doi:10.1007/s40279-015-0318-7

Hagiwara N. Muscle fibre types: their role in health, disease and as therapeutic targets. OA Biology 2013 Nov 01;1(1):2.

Hernelahti, M., Tikkanen, H. O., Karjalainen, J., & Kujala, U. M. (2005). Muscle Fiber-Type Distribution as a Predictor of Blood Pressure: A 19-Year Follow-Up Study. Hypertension,45(5), 1019-1023. doi:10.1161/01.hyp.0000165023.09921.34

Hochachka, P.W. (1998) Mechanism and evolution of hypoxia-tolerance in humans. J. Exp. Biol. 201, 1243–1254

Karjalainen, J., Tikkanen, H., Hernelahti, M., & Kujala, U. M. (2006). Muscle fiber-type distribution predicts weight gain and unfavorable left ventricular geometry: a 19 year follow-up study. BMC Cardiovascular Disorders,6(1). doi:10.1186/1471-2261-6-2

Ogden C. L., Carroll, M. D., Lawman, H. G., Fryar, C. D., Kruszon-Moran, D., Kit, B.K., & Flegal K. M. (2016). Trends in obesity prevalence among children and adolescents in the United States, 1988-1994 through 2013-2014. JAMA, 315(21), 2292-2299.

Ruiz, J. R., Sui, X., Lobelo, F., Morrow, J. R., Jackson, A. W., Sjostrom, M., & Blair, S. N. (2008). Association between muscular strength and mortality in men: prospective cohort study. Bmj,337(Jul01 2). doi:10.1136/bmj.a439

Tanner, C. J., Barakat, H. A., Dohm, G. L., Pories, W. J., Macdonald, K. G., Cunningham, P. R., . . . Houmard, J. A. (2001). Muscle fiber type is associated with obesity and weight loss. American Journal of Physiology – Endocrinology And Metabolism,282(6). doi:10.1152/ajpendo.00416.2001

Volaklis, K. A., Halle, M., & Meisinger, C. (2015). Muscular strength as a strong predictor of mortality: A narrative review. European Journal of Internal Medicine,26(5), 303-310. doi:10.1016/j.ejim.2015.04.013

The Testosterone and Fertility Conundrum: A Western Perspective

2750 words

Some people are scared of testosterone. This is no surprise, since a super-majority of people have no background in the human sciences. I’m sure plenty men know what it’s like to have low testosterone, just like some men know what it’s like to have higher T levels than average. What is the optimum level of testosterone? Why are some people scared of this hormone?

Rushton (1997) posited that r/K Selection Theory could be used to classify the races of Man on a spectrum, going from r-selection (having many children but showing little to no parental care) to K-selection (having fewer children but showing a lot of parental care). He stated that the traits of the races were also on the r/K spectrum, with the races having stark differences in morphology. Rushton’s application of r/K theory to humans isn’t completely wrong, though I do have some problems with some of his claims, such as his claims that the races differ in average penis size. He contends that testosterone is the cause for higher crime rates for black Americans and higher rates of prostate cancer in black Americans compared to white Americans.

However, in 2014, Richard et al showed that when controlling for age, blacks had 2.5 to 4.9 percent more testosterone than whites, on average. This cannot explain racial differences in prostate cancer. However, some people may emphatically claim that the races differ in average testosterone, with blacks having 13 percent higher free testosterone than whites on average. The citation that gets used the most to prove that blacks supposedly have higher testosterone than whites is Ross et al (1986), which is based on a sample of 100 people (50 black, 50 white). He claims that it’s when T levels are higher, so it’s a ‘better study’ even though the sample leaves a lot to be desired. A much more robust study showed that the difference was negligible, and not enough to account for the differential prostate cancer rates between the races.

Rohrmann et al (2007) show that there are no differences in circulating testosterone between blacks and whites in a nationally representative sample of American men. Mexicans had the highest levels. There were, however, B-W differences in estradiol production. They couldn’t confirm the other studies that stated that blacks had higher testosterone, possibly due to variations in age or using non-representative samples (that’s the culprit). Their nationally representative sample showed there was no difference in testosterone between blacks is whites, while the meta-analysis showed by Richard et al (2014) showed the difference was negligible at 2.5 to 4.9 percent higher rate of testosterone which doesn’t explain why blacks have a higher rate of acquiring prostate cancer.

The much more likely culprit for blacks having higher rates of prostate cancer, as I have written about before, are environmental factors. The two main factors are receiving less sunlight and diet. There is no evidence that higher levels of testosterone lead to prostate cancer (Michaud, Billups, and Partin, 2015). Contrary to those who say that higher levels of T cause prostate cancer, there is growing evidence that lower levels of T lead to prostate cancer (Park et al, 2015). Put simply, there is no evidence for testosterone’s supposed impact on the prostate (Stattin et al, 2013).

Differences in androgen/androgen receptors have been explained as a cause for racial differences in prostate cancer (Pettaway, 1999), however, these results haven’t been consistent (Stattin et al, 2003) and these differences in circulating androgen may possibly be explained by differences in obesity between the two populations (Gapstur et al, 2002; also see my posts on obesity and race).

Due to the ‘testosterone scare’, some people may believe that having low T is a ‘good thing’, something that’s preferred over being a high T savage. However, testosterone and the androgen receptor gene polymorphism are both associated with competitiveness and confidence in men (Eisenegger et al, 2016) and a reduced risk of cardiovascular disease in elderly men (Ohlsson et al, 2011). Obviously, lower testosterone is related to less overall confidence. People who have the thought in their head that testosterone is a ‘bad hormone’ will believe the negativity about it in the media and popular headlines.

Testosterone alone does not cause violence, but it does cause men to be socially dominant. Testosterone has been shown to increase in the aggressive phases of sports games and when shown artificial humans made to invoke physiologic responses, leading some researchers to argue that testosterone should be classified as a stress hormone. Testosterone does change based on watching one’s favorite soccer team winning or losing in a sample of 21 men (Bernhardt et al, 1998), lending some credence to the claim that testosterone is and should be classified as a stress hormone. Also of interest is that men who administered high levels of testosterone did not report higher levels of aggression (Batrinos, 2012).

I’ve heard some people literally say that having low testosterone is ‘a good thing’. People say this out of ignorance. There are a whole slew of problems associated with low testosterone, including but not limited to: insulin resistance in diabetic men (Grossmann et al, 2008); metabolic syndrome (Tsuijimura et al, 2013); muscle loss (Yuki et al, 2013); stroke and transient ischemic attack (a mini-stroke; Yeap et al, 2009); associated with elevated risk for dementia in older men (Carcaillon et al, 2014); myocardial infarction (heart attack) in diabetic men (Daka et al, 2015) etc. So it seems that the fear of testosterone from those in the anti-testosterone camp are largely blown out of proportion.

Testosterone is also a ‘food’ for the brain, with low levels being related to mental illness, sexual dysfunction, lower quality of life and cognitive impairment (Moffat et al, 2011) in both sexes (Ciocca et al, 2016). Noticed in both men in women with testosterone deficits were: cognitive impairment (reduction of working memory, episodic memory, processing speed, visual-spatial functioning and executive performance); a decrease in sexual activity; anxiety, schizophrenia, depression and stress; and alterations in cortical thickness in the brain. The fact that testosterone is so heavily important to the body’s central functioning is extremely clear. This is why it’s laughable that some people would be happy and brag about having low testosterone.

I recently came across a book called The Testosterone Hypothesis: How Hormones Regulate the Life Cycles of Civilization. Barzilai’s main premise is that the rise and fall of the West is mediated by the hormone testosterone, and due to lower testosterone levels this is one large reason for what is currently occurring in the West. The book has an extremely interesting premise. Barzilai’s hypothesis does line up with the declining levels of testosterone in America (Travison et al, 2007) though other research shows no decline in American testosterone levels from the years 88-91 to 99-04 (Nyante et al, 2007). Moreover, men who had higher level of n-6 in their blood then n-3 were far more likely to be infertile (Safarinejad et al, 2010) a marker of low testosterone (Sharpe, 2012). The ratio of n-6 to n-3 from the years 1935 to 1939 were 8.4 to 1, whereas from the years 1935 to 1985, the ratio increased to about 10 percent (Raper et al, 1992). The ratio of n-6 to n-3, on top of lowering sperm count (which is correlated with testosterone) also has negative effects on male and female cognitive ability (Lassek and Gaulin, 2011).

Barzilai’s research also corroborates Rushton’s (1986) theory of why there are lower birthrates for Europeans around the world. Rushton stated that this cycle has been noticed throughout history, with empires rising and falling due to differential birthrates between the ruling class and the ruled. Rushton also hypothesized that the cultures and gene pools associated with the Graeco-Roman empire were “evolutionary dead ends” (Rushton, 1986: 148). Knowing what we now know about the relationship between cognitive ability, testosterone, and fertility, we now have a plausible hypothesis for Rushton’s hypothesis and one of the (many) reasons why the Graeco-Roman empire collapsed. Rushton further hypothesized that the cause for lower fertility in European populations “may be partly mediated by a psychological process in which the desire to be in control of both oneself and one’s environment is taken to an extreme.” Of course there’s a good chance that this psychological process is mediated/influenced by testosterone.

Europe is the continent with the lowest fertility (ESHRE Capri Workshop Group, 2010). Testosterone has declined in Europe as a whole (Rivas et al, 2014), and this is a strong cause for the lower birthrates in Europe (along with genetic reasons) and in Finland (Perheentupa et al, 2013). The introduction of Westernized diets lowers testosterone, so this is no surprise that a reduction is seen in countries that begin to consume a Western diet. Another probable cause for lower testosterone/fertility in Europe at the moment is the large number of European men that died in WWI and WWII. Those that were more willing to fight died, meaning there was less of a chance he spread his genes. So, over time, this lead to the current cucking of Europe that we are now witnessing.

Testosterone is also hypothesized to have driven evolution (Howard, 2001). Testosterone is such an important part of human evolution and development, so much so that if we had a lower level of the hormone all throughout our evolution that we would be a different species today. Testosterone is needed for sexual functioning, good mental and brain health, fertility, cognitive ability, muscle mass retention in both young and old men, etc. Testosterone is one of the most important hormones for both men and women, and low levels for both sexes are detrimental to a high quality of life. The current data on testosterone and prostate cancer shows that higher levels of testosterone don’t contribute to prostate cancer. Testosterone, then, also isn’t a cause for the racial gap in prostate cancer because other environmental factors better explain it. If people really are happy about having lower testosterone, then I hope they have fun living a life with a low sex drive, lower cognition in old age, lower muscle mass and a higher chance of stroke and metabolic syndrome.

One of the most interesting things about testosterone is the possibility that it explains why civilizations rise and fall. There is anecdotal evidence from Rushton, as well as his theorizing that the higher classes in Rome didn’t breed which led to their downfall. We now know that lower fertility rates for men are associated with lower testosterone, so along with Barzilai’s thesis of testosterone causing the rise and fall of civilizations, Rushton’s theorizing of the cause of lower European fertility and the cause of the fall of the Graeco-Roman empire.

Testosterone is an extremely important hormone, one that drives human evolution and society formation since it’s associated with dominance and confidence. Low testosterone is looked at as ‘good’ because those with higher intelligence have lower levels of the hormone (indicated by lower confidence and having sex at a later age). I showed that the higher IQ East Asian men have a problem finding dates and being looked at as sexually attractive (even though they rated themselves as average). Along with lower East Asian fertility, specifically in Japan, does it seem to you like the high IQ people are more desired if they are having problems keeping their birthrates up? The fact of the matter is, lower levels of testosterone are correlated with lower levels of fertility. If men don’t have as much testosterone pumping through their veins, they will be less likely to have sex and thusly reproduce.


Batrinos, M. L. (2012). Testosterone and aggressive behavior in man. International Journal of Endocrinology & Metabolism,10(3), 563-568. doi:10.5812/ijem.3661

Bernhardt, P. C., Jr, J. M., Fielden, J. A., & Lutter, C. D. (1998). Testosterone changes during vicarious experiences of winning and losing among fans at sporting events. Physiology & Behavior,65(1), 59-62. doi:10.1016/s0031-9384(98)00147-4

Carcaillon, L., Brailly-Tabard, S., Ancelin, M., Tzourio, C., Foubert-Samier, A., Dartigues, J., . . . Scarabin, P. (2014). Low testosterone and the risk of dementia in elderly men: Impact of age and education. Alzheimer’s & Dementia,10(5). doi:10.1016/j.jalz.2013.06.006

Ciocca G, Limoncin E, Gravina GL, et al. Is testosterone a food for brain? Sex Med Rev 2016;4:15-25.

Daka, B., Langer, R. D., Larsson, C. A., Rosén, T., Jansson, P. A., Råstam, L., & Lindblad, U. (2015). Low concentrations of serum testosterone predict acute myocardial infarction in men with type 2 diabetes mellitus. BMC Endocrine Disorders,15(1). doi:10.1186/s12902-015-0034-1

ESHRE Capri Workshop Group. Europe the continent with the lowest fertilityHum Reprod Update 2010; 16: 590–602.

Eisenegger, C., Kumsta, R., Naef, M., Gromoll, J., & Heinrichs, M. (2016). Testosterone and androgen receptor gene polymorphism are associated with confidence and competitiveness in men. Hormones and Behavior. doi:10.1016/j.yhbeh.2016.09.011

Gapstur SM, Gann PH, Kopp P, Colangelo L, Longcope C, Liu K. Serum androgen concentrations in young men: a longitudinal analysis of associations with age, obesity, and race—the CARDIA male hormone study. Cancer Epidemiol Biomarkers Prev 2002; 11: 10417

Grossmann, M., Thomas, M. C., Panagiotopoulos, S., Sharpe, K., Macisaac, R. J., Clarke, S., . . . Jerums, G. (2008). Low Testosterone Levels Are Common and Associated with Insulin Resistance in Men with Diabetes. The Journal of Clinical Endocrinology & Metabolism,93(5), 1834-1840. doi:10.1210/jc.2007-2177

Howard JM (2001): Androgens in human evolution. A new explanation of human evolution.

Lassek, W. D., & Gaulin, S. J. (2011). Sex Differences in the Relationship of Dietary Fatty Acids to Cognitive Measures in American Children. Frontiers in Evolutionary Neuroscience,3. doi:10.3389/fnevo.2011.00005

Michaud, J. E., Billups, K. L., & Partin, A. W. (2015). Testosterone and prostate cancer: an evidence-based review of pathogenesis and oncologic risk. Therapeutic Advances in Urology,7(6), 378-387. doi:10.1177/1756287215597633

Moffat, S. D., Zonderman, A. B., Metter, E. J., Blackman, M. R., Harman, S. M., & Resnick, S. M. (2002). Longitudinal Assessment of Serum Free Testosterone Concentration Predicts Memory Performance and Cognitive Status in Elderly Men. The Journal of Clinical Endocrinology & Metabolism,87(11), 5001-5007. doi:10.1210/jc.2002-020419

Nyante, S. J., Graubard, B. I., Li, Y., Mcquillan, G. M., Platz, E. A., Rohrmann, S., . . . Mcglynn, K. A. (2011). Trends in sex hormone concentrations in US males: 1988-1991 to 1999-2004. International Journal of Andrology,35(3), 456-466. doi:10.1111/j.1365-2605.2011.01230.x

Ohlsson C, Barrett-Connor E, Bhasin S, et al. High serum testosterone is associated with reduced risk of cardiovascular events in elderly men: the MrOS (Osteoporotic Fractures in Men) study in Sweden. J Am Coll Cardiol. 2011; 58(16):1674-1681.

Park, J., Cho, S. Y., Jeong, S., Lee, S. B., Son, H., & Jeong, H. (2015). Low testosterone level is an independent risk factor for high-grade prostate cancer detection at biopsy. BJU International,118(2), 230-235. doi:10.1111/bju.13206

Perheentupa, A., Makinen, J., Laatikainen, T., Vierula, M., Skakkebaek, N. E., Andersson, A., & Toppari, J. (2012). A cohort effect on serum testosterone levels in Finnish men. European Journal of Endocrinology,168(2), 227-233. doi:10.1530/eje-12-0288

Pettaway CA. Racial differences in the androgen/androgen receptor pathway in prostate cancer. J Natl Med Assoc 1999, 91: 653:650

Raper, N. R., Cronin, F. J., & Exler, J. (1992). Omega-3 fatty acid content of the US food supply. Journal of the American College of Nutrition,11(3), 304-308. doi:10.1080/07315724.1992.10718231

Richard, A., Rohrmann, S., Zhang, L., Eichholzer, M., Basaria, S., Selvin, E., . . . Platz, E. A. (2014). Racial variation in sex steroid hormone concentration in black and white men: a meta-analysis. Andrology,2(3), 428-435. doi:10.1111/j.2047-2927.2014.00206.x

Rivas AM, Mulkey Z, Lado-Abeal J, Yarbrough S. Diagnosing and managing low serum testosteroneProc (Bayl Univ Med Cent) 2014;27:321-324

Rohrmann, S., Nelson, W. G., Rifai, N., Brown, T. R., Dobs, A., Kanarek, N., . . . Platz, E. A. (2007). Serum Estrogen, But Not Testosterone, Levels Differ between Black and White Men in a Nationally Representative Sample of Americans. The Journal of Clinical Endocrinology & Metabolism,92(7), 2519-2525. doi:10.1210/jc.2007-0028

Ross R, Bernstein L, Judd H, Hanisch R, Pike M, Henderson B. Serum testosterone levels in healthy young black and white men. J Natl Cancer Inst. 1986 Jan;76(1):45–48

Rushton, J. P. (1986). Gene-Culture Coevolution and Genetic Similarity Theory: Implications for Ideology, Ethnic Nepotism, and Geopolitics. Politics and the Life Sciences,4(02), 144-148. doi:10.1017/s0730938400004706

Rushton J P (1997). Race, Evolution, and Behavior. A Life History Perspective (Transaction, New Brunswick, London).

Safarinejad, M. R., Hosseini, S. Y., Dadkhah, F., & Asgari, M. A. (2010). Relationship of omega-3 and omega-6 fatty acids with semen characteristics, and anti-oxidant status of seminal plasma: A comparison between fertile and infertile men. Clinical Nutrition,29(1), 100-105. doi:10.1016/j.clnu.2009.07.008

Sharpe, R. M. (2012). Sperm counts and fertility in men: a rocky road ahead. EMBO reports,13(5), 398-403. doi:10.1038/embor.2012.50

Stattin, P., Lumme, S., Tenkanen, L., Alfthan, H., Jellum, E., Hallmans, G., . . . Hakama, M. (2003). High levels of circulating testosterone are not associated with increased prostate cancer risk: A pooled prospective study. International Journal of Cancer,108(3), 418-424. doi:10.1002/ijc.11572

Travison, T. G., Araujo, A. B., O’Donnell, A. B., Kupelian, V., & Mckinlay, J. B. (2007). A Population-Level Decline in Serum Testosterone Levels in American Men. The Journal of Clinical Endocrinology & Metabolism,92(1), 196-202. doi:10.1210/jc.2006-1375

Tsujimura, A., Miyagawa, Y., Takezawa, K., Okuda, H., Fukuhara, S., Kiuchi, H., . . . Nonomura, N. (2013). Is Low Testosterone Concentration a Risk Factor for Metabolic Syndrome in Healthy Middle-aged Men? Urology,82(4), 814-819. doi:10.1016/j.urology.2013.06.023

Yeap, B. B., Hyde, Z., Almeida, O. P., Norman, P. E., Chubb, S. A., Jamrozik, K., . . . Hankey, G. J. (2009). Lower Testosterone Levels Predict Incident Stroke and Transient Ischemic Attack in Older Men. Endocrine Reviews,30(4), 411-411. doi:10.1210/edrv.30.4.9994

Yuki, A., Otsuka, R., Kozakai, R., Kitamura, I., Okura, T., Ando, F., & Shimokata, H. (2013). Relationship between Low Free Testosterone Levels and Loss of Muscle Mass. Scientific Reports,3. doi:10.1038/srep01818