In 2020, a company called Genomic Prediction began offering genomic scores for diabetes, skin cancer, high blood pressure, high cholesterol, intellectual disability, and “idiopathic short stature.” They have stopped advertising the last two “because it’s too controversial.” Keep in mind, no, because the effects are minor and the science is unreliable. The theoretical maximum for height would be a difference of 2.5 inches in polygenic scores, and that theoretical maximum has not yet been seen, even in studies of Europeans. Polygenic scores for most other traits lag far behind. (And that’s just one company; another company called HeraSite has since made the move and claims to offer embryo selection based on intelligence.)
Remember, the more traits a person chooses, the less accurate each prediction is. Furthermore, many genes influence many biological processes, so a gene implicated in one undesirable trait may have as-yet undefined effects on other desirable traits.
And all this ignores the potential influence of the child’s environment. The first couple to use genetic testing for their daughter chose an embryo that had a low risk of developing heart disease; Their risk was 1 percent lower than that of the three embryos they rejected. It would have been cheaper and probably more effective to feed him vegetables and get him on the football team.
Risks of reduction in genetic diversity
Almost every family I know has a child who has taken growth hormone, and many of them also receive tutoring. These interventions are rarely distributed evenly. But if embryos are selected based on polygenic scores, the authors fear that a new form of social inequality could arise. While growth hormone injections affect only one individual, selection of embryos based on polygenic score further affects all descendants of that embryo. So the offspring of selected embryos may eventually be regarded as a new class of adapted people, whose status may be elevated simply because their parents can afford to scrutinize their embryo’s genome – even if their “genetic” capabilities are actually quite different from everyone else’s.
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