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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.

Conclusion

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.