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Prenatal Testing to Screen for Diseases is Eugenic: The Eugenic Nature of Prenatal Testing

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The concept of eugenics has a long history. Back in 2018, I surveyed the history of eugenics throughout antiquity to the modern day in different countries. It seems that the Greeks were the first to employ the concept. Both Aristotle and Plato wanted the state go be in charge of the birthing process, which is a classical definition of eugenics. People have even been sterilized in recent history, as recent as 20 years ago in California.

After the defeat of the Nazis in WW2, though, such eugenic ideas have never left. They have just changed form. We are in the new millennium and so we have new technologies that may allow us to screen for certain disseases and terminate then early on in the process. In this article, I will argue that using such technologies to prevent the births of such people are eugenic. I will give a few arguments and then I will connect them.

The “new eugenics”, same as the old eugenics

“New eugenics” refers to the use of advanced genetic technologies to improve or enhance genetic traits of humans or to selectively breed humans with desired traits while discouraging or preventing the reproduction of those with undesired traits. This tracks with “classical eugenics”, which was a socio-political movement in the late 18th to early 19th century which aimed at improving the human gene pool through encouraging the selective breeding of those with desirable traits while discouraging or preventing the reproduction of those with undesired traits, through coercion such as forced sterilization and euthanasia of individuals who have undesired traits like mental illness, physical disabilities or criminal tendencies. So as can be seen, both the old and new eugenics both involve the same basic practice of selective breeding of humans based on their genetic traits. Thus, both forms of eugenics are reductive in nature.

Both kinds of eugenics are morally wrong. By “morally wrong” I mean that it is not in accordance with accepted ethical principles and values. So calling eugenics “morally wrong” indicates that it is ethically unacceptable to most people, since it goes against the fundamental principles of human dignity, social justice, and human autonomy.

It’s a violation of human dignity and autonomy (Zaluski, 2010) since it makes decisions about a person’s life and reproductive choices based on their genetic makeup rather than their own desires and preferences. It can also stigmatize certain groups while perpetuating existing socio-economic inequalities by reinforcing the dominance of certain groups while marginalizing others. So it can result in further stigmatization and discrimination of certain groups based on their perceived genetic traits which would then lead to a loss of social cohesion along with a decrease in societal well-being. Selective breeding can also lead to a loss of genetic diversity in humans, which could then have further negative effects on our species’ ability for long-term survival and adaptation. And there are concerns involving the new eugenics like gene editing and PGD while there of course could be unintended, unforseen consequences and side effects while new forms of inequality and discrimination could emerge.

So here is the argument that eugenics is morally wrong.

P1: If a practice involves the selective breeding of humans based on their genetic traits, it is permissible only if it respects the autonomy and dignity of all individuals involved.
P2: Eugenics involves the selective breeding of humans based on their genetic traits.
P3: Eugenics does not respect the autonomy and dignity of all individuals involved.
C: Therefore, eugenics is morally wrong.

Premise 1 can be defended by the idea that every human has inherent value and deserves to be treated with respect and dignity regardless of their genetic makeup. Premise 2 is an accepted feature of both the old and the new eugenics. Premise 3 can be supported on the basis that eugenic practices involve the imposition of genetic traits on individuals without their consent, and it could also lead to the stigmatization and marginalization of those with so-called undesired genetic traits which would violate the fundamental ethical principles of human dignity and autonomy. So from (1), (2), and (3), and Conclusion follows that eugenics is morally wrong since it involves the selective breeding of humans based on their genetic traits while failing to respect the autonomy and dignity of all individuals involved.

Eugenics won’t work because genetic reductionism is false

Genetic reductionism is the view that genes are the primary determinants of human traits. It is the view that complex traits and behaviors can be reduced to and explained by genetic and biological factors while non-genetic and environmental factors are insignificant determinants. In the eugenic view—and in the view of most people—traits are primarily genetically caused, and by using genetic engineering and similar new-age tools, we can then guide out evolution and prune out both genes that lead to undesired traits and, in effect, people too. However, genetic reductionism is false. It is false because there is no privileged causal role in development of any of the developmental resources, genes included (Noble, 2012). So it then follows that eugenics can’t work, since eugenics is genetically reductionistic, and genetic reductionism is false. So the practice of eugenics is unlikely to work and may lead to unintended consequences. Here’s the formalized argument:

P1: If eugenics is based on the assumption that genetic traits are the primary determinants of human traits, then eugenics is genetically reductionistic.
P2: Eugenics is based on the assumption that genetic traits are the primary determinants of human traits.
P3: Genetic reductionism is false.
C: Therefore, eugenics cannot work.

Just like eugenics is genetically reductionistic, so is hereditarianism and that’s also why hereditarianism cannot work. And many hereditarians, like Lynn, Jensen, Shockley, and Cattell held eugenic views (just like Murray and Herrnstein, but they were much more careful with their language, though the underlying ideas are the same) and they are, of course, genetic reductionists. It is, after all, with the advent of IQ tests that eugenics had it’s start in America, and that’s one of the reasons why IQ tests should be banned, since they can and have led to morally wrong policies.

New genetic technologies are eugenic

I have given a pro- and anti-argument for the use of preimplantation genetic diagnosis (PGD) back in 2018. PGD is a procedure which allows parents to screen embryos for genetic abnormalities before implatiation during IVF. This process is often based on the desire to avoid certain traits or to select for certain desirable traits. As I argued above, the new boss is the same as the old boss—the new eugenics has similar end-goals as the old eugenics. PGD doesn’t involve coercion or forced sterilization like the old eugenics, yet it still has intended goals which are similar to the old eugenics by creating “genetically better” people by selecting for certain genes while avoiding others, under the assumption of genetic causation of socially-desired and undesired traits. This can then lead to the homogenization of our species, since people with certain traits could become more common while others without them become rarer. This can also lead to the discrimination of those who do not have the desired traits. Thus, PGD is a form of new eugenics and it is eugenic because it has the same end-goals as the old eugenics.

P1: If PGD isn’t a form of new eugenics, then it does not involve a selective breeding process based on genetic traits that can lead to a homogenization of the human population and discrimination against those who do not possess the desired traits.
P2: PGD does involve a selective breeding process based on genetic traits that can lead to a homogenization of the human population and discrimination against those who do not possess the desired traits.
C: Therefore, PGD is a form of new eugenics.

I have already provided an argument which establishes that eugenics is morally wrong. Now here are a few more arguments which establish PGD as a eugenic practice.

P1: If prenatal testing is used to screen for diseases to abort babies, then it is selectively terminating those with undesirable genetic traits.
P2: If selective termination of those with undesirable genetic traits is practice then it is a eugenic practice.
C: Thus, if prenatal testing is used to screen for diseases to abort babies, then it is a eugenic practice.

P1: If prenatal testing is not a eugenic practice, then it is not selectively terminating those with undesirable genetic traits.
P2: Prenatal testing is selectively terminating those with undesirable genetic traits.
C: Therefore prenatal testing is a eugenic practice.

P1: If a practice is eugenic, then it involves the selective breeding or termination of individuals with undesirable genetic traits.
P2: Prenatal testing involves the selective termination of individuals with undesirable genetic traits.
C: Therefore, prenatal testing is a eugenic practice.

As can be seen, it is quite obvious that the new eugenics is the same as the old eugenics and the goals shared are very similar. Thus, the only distinction between old and new eugenics is that for the new eugenics there is no state coercion for the use of the new genetic technologies to screen for undesired traits like diseases. In this regard, it is used negatively, but there is though the chance that it will be used positively. By “negative” and “positive” I’m referring to negative and positive eugenics.

Now, I can connect the arguments I’ve made and argue that eugenics is morally wrong and that it rests on the false premise of genetic reductionism.

P1: If prenatal testing is used to screen for diseases to abort babies, then it is a eugenic practice.
P2: If selective breeding or termination of individuals with undesirable genetic traits is a eugenic practice, then eugenics is based on the false premise of genetic reductionism.
P3: Eugenics that is based on the false premise of genetic reductionism ignores the complex interplay between genetics, environmental factors and other developmental resources and fails to fully appreciate the inherent worth and value of every human being.
C: Therefore, using prenatal testing to screen for diseases to abort babies is a form of eugenics that is based on the false premise of genetic reductionism and is morally wrong.

IQ, embryo selection and PGS

While we have already begun to implement such tools and methods in the public, a recent study concluded that testing embryos for complex traits like height and IQ is “premature”, with the top-scoring PGS embryos gain would be approximately equal to 2.5cm in height and 2.5 IQ points (Karavani et al, 2019). But these values were derived from PGS which were derived from GWAS, so it’s just based on correlation. Most authors of course assume that “intelligence” is “highly polygenic”, they need not only correlation, but a mechanism (Munday and Savalescu, 2021). Unfortunately, the eugenic dreams of IQ-ists to increase IQ through these methods won’t work. Since one’s IQ is a function of the type of psychological and cultural tools they are exposed to from birth, and the items on the test are biased towards a certain social class, there are known ways to increase IQ that don’t have anything to do with genetically reductionist GWAS/PGS/PGD pipe dream. The argument can be made like this:

P1: The potential gain of embryo screening for traits such as height and cognitive ability is not significant.
P2: The gain due to embryo screening for height and cognitive ability is small, with an average gain of only ≈2.5 cm for height and ≈2.5 IQ points for cognitive ability.
C: Therefore, there is no significant case for using preimplantation genetic diagnosis to select embryos for implantation based on height or cognitive ability.

Of course, this doesn’t mean that even if the so called gains were significant and that PGS were causal that we should use PGD to select those traits


Although it has been said that common arguments against genetic reductionism rest on a strong version of genetic reductionism/determinism, and so the arguments “are therefore unsound” (Resnick and Vorhaus, 2006). The kinds of arguments, assumptions and considerations in this discussion of genetic modification and PGD assume, also, any kind of genetic determinism of traits.

At the end of the day, methods like PGD can lead to the destruction of fetuses on the basis of its genetic constitution. Eugenic selection could also have unintended consequences in the future since genetic variance could be reduced which would impinge on one’s ability to choose a partner, so it would lead to a limitation in partners for future people. Irrespective of the moral arguments made here, I think that the open future argument makes the best case against genetic modification of humans. This will yet again be another argument from human autonomy. Not only will we be impinging on one’s individual autonomy, but we don’t even know what kind of traits could be desirable from a survival point of view in the future. So that’s another reason to not genetically modify embryos or to select certain embryos over others.

P1: Future people have a moral right to choose (or not) the characteristics of their own genome.
P2: Genetic modification of an embryo involves making choices about the characteristics of the future person’s genome.
C: Therefore genetic modification of an embryo is morally impermissible since it violates the moral right of the future person to choose (or not choose) the characteristics of their own genome.

While genetic reductionism is a form of biological determinism, there is also what is called epigenetic determinism. Any kind of reducing X to deterministic proclivities is false. Nevertheless, I have distinguished between the old and the new eugenics, and showed that the only difference between them is that in the new eugenics, there is no state-sponsored coercion or forced sterilization occurring. (Although that, sadly still happens today.) Since genetic reductionism is false, then any attempt to “defend eugenics” (Anomaly, 2018; Wilson, 2019; Veit et al, 2021) are doomed to fail. But genetic engineering “is objectionable because it represents a bid for mastery and dominion that fails to appreciate the gifted character of human powers and achievements” (Sandell, 2007).


Arguments For and Against Preimplantation Genetic Diagnosis

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Like abortion, preimplantation genetic diagnosis (PGD) is feared. This is due, in part, to fears of eugenics coming back through a “backdoor” with the advent of new technology such as CRISPR/CAS9 and other types of tools we can use to genetically modify ourselves. The case of PGD—just like abortion—has been heavily debated in recent times, more so due to the recent strides in genomics we have made since the advent of the Human Genome Project.

PGD offers us a method to identify embryos with genetic diseases. Understandably, this has raised caution with some, due to the strong link with eugenic thinking/policies. See The Ethical Implications of Preimplantation Genetic Diagnosis. Thus, by scanning the genomes of fetuses, we can then see if they have a higher chance of acquiring any disease and select fetuses which have a lower to nonexistent chance of acquiring said disease.

An argument against PGD

In his paper Just diagnosis? Preimplantation genetic diagnosis and injustices to disabled people, Peterson (2005) presents one slippery slope argument against PGD (Freeman, 1996) (and later provides a refutation). The argument that Peterson (2005) presents is a “slippery slope” argument—that is, it’s an argument which argues that if we allow X, then since we allowed X, then horrible thing Y can and will follow. Peterson (2005) articulates the argument thus:

As situation A (the use of PGD to select against severe genetic diseases) is refined, “it will be difficult, if not impossible, to contain the uses of such research”. A will therefore bring about situation B, where PGD will be used to select against mild or perhaps non-medical conditions.

Besides the refinement of A, B will be brought about because “There will likely be an increasing pressure … on people to take advantage of these techniques, and not bring even a mildly disabled child into the world …”.

Finally, we could reach a morally abhorrent outcome Z, which is disturbingly close to eugenics, where our notion of the moral equality of all human beings, including those with disabilities, is undermined.

Z is so morally bad, that it outweighs the benefits of undertaking A.

Therefore, A should not be undertaken.

This argument, in my view, seems to be appealing to emotion by saying that since we can reach morally abhorrent outcome Z (a type of eugenics), then we should not continue with this practice. However, others argue that this discriminates against people with disabilities (see Katthab, 2009). Peterson (2005) argues that Freeman’s (1996) argument “lacks empirical support” and so it makes the conclusion difficult to assess; technology can and will be regulated which would quell any fears of possible use of this technology for any eugenic ideals; and, through using PGD, we can use it to “fight the obvious causes of discrimination, such as intolerance and egoism“, which would, in turn, reduce discrimination. Lastly, addressing Freeman’s (1996) concerns that PGD would lead to the discrimination of currently disabled persons, Peterson (2005) claims that “even if we accept that PGD will generate discrimination against disabled people, it is far from obvious that this is sufficient to warrant its moral condemnation.” Thus, Peterson (2005) concludes that Freeman’s (1996) argument is not sufficient to end the use of PGD technology. (Also see Robertson, 2003 for the view that “except for sex selection of the first child, most current extensions of PGD are ethically acceptable“.)

Many arguments against PGD rely on the concept of a fetus as a person and terminating any fetus with any prospective disease is paramount to killing a person. Others, of course, hinge on the fact that PGD does help reduce the risk of a babe being born with deleterious diseases, it does not completely ameliorate any generic risk for disease and so the fetus must be monitored through conception up until pregnancy to be sure that no disease appears during conception. And, of course, certain diseases that may hamper one’s quality of life may not appear until one reaches adolescence, adulthood, middle or old age. This is another fact against PGD: that even selecting embryos that apparently have no risk for disease, they may acquire diseases in older age which would not be seen since some diseases only generate symptoms at certain stages of life.

One final objection to PGD is also moral: it could, and will, send a message to any individuals currently alive that their lives are somehow “less” than others, since individuals with a chance to acquire said disease are selected against, as McConachy (2010) argues.

Lastly, Richardson (2017: 155-157) argues that the selection of embryos with so-called “potential” is ill-founded since they talk about vague concepts such as “egg quality”. Differences in potential lie, supposedly, in the “genetic blueprint” (see my article DNA Is not a Blueprint for arguments against that notion), though “That view implies that differences in individuals in important functions are largely due to differences in genes. As we have seen, though, things are far from being so simple” (Richardson, 2017: 156).

An argument for PGD

PGD can be used for many things; most importantly, screening the genome of a perspective fetus before IVF. Though, this has led some to worry that this could be a way in which eugenics can “sneak in through the backdoor” by virtue of making people with diseases more likely to be discriminated against since “disabled phenotypes” would slowly be phased out by PGD. One argument for could be:

Parents have rights; if parents have rights, then they have the right to do what they want with their children, and they want to do what is best for their children; therefore a parent should have the right to use PGD to select the best-possible embryo for implantation.

This is where we think of the implications of aborting a fetus, or not implanting a fetus that has a higher chance of acquiring any disease. There are, of course, certain people who would willingly select embryos which have a high chance to be disabled, because they themselves are disabled or they believe they “should be” disabled themselves and so want disabled children. Since parents have rights, as can be seen in the reasoning chain above, then parents should be able to choose the status of their babe. But if the babe’s quality of life is low, then is it ethical for that person to select an embryo with a high chance of acquiring a disease?

Another argument “for” PGD can be:

Humans should not suffer; if we can prevent human suffering with our current technology, then we have a moral imperative to do whatever is in our power to do so; if we can prevent low qualities of life for any embryo E, then we should do so; therefore, we should screen embryos for diseases that can and will lower their qualities of life and select against these embryos.

One may argue that a fetus may not have a “moral right” to life (see Tooley, 1972), though, if we know that a fetus has a high chance to have such a debilitating disease such that it lowers its quality of life, then it should be aborted/not implanted in the womb. Religious views, of course, come into play here but I am not worried about them; I am worried only about sound arguments for them. (See Fasoulioutis and Schenker, 1997 for these views.)

PGD may, of course, prevent abortions of said fetus since we know that the fetus in question may have a higher chance of acquiring a certain disease, so if one is against abortion, then they may be for the use of PGD to screen the fetuses’ genome to scan for any readily apparent problems in their genome in regard to the acquiring of certain genetic diseases.

Arguments for PGD hinge on parents wanting the best possible lives for the children they conceive and the arguments really rely on parental autonomy, the parent’s want to choose how their kid is born, if their chance for disease is high or not (which also would turn to “designer babies”; an argument against “designer babies” will be erected soon. If parents can do what’s best for an unborn child then, most would argue  they have a moral imperative to give the babe the best possible life and so they should abort/select against certain embryos which have a high chance of acquiring diseases.


There do not seem to be as many strong arguments against PGD compared to abortion. Though one can use the basic blueprint of the argument against abortion and liken it to PGD. The PGD debate is similar to the abortion debate. One can use similar arguments against abortion to argue against PGD.

These debates are both ethical scientific: we have the ability to now do X which would stop suffering Y in embryo E. Just because we can do something, does that mean we should do so? Like with the editing of the germline, we don’t know what types of consequences would occur since we have, pretty much, no experience in editing the germline/genes of humans in a large-scale way.