Polygenic screening

Polygenic screening' or embryo selection is the practice of using statistical analysis to filter out defective embryos. It is a means of the new, liberal eugenics as opposed to the old, racist eugenics.

Quotes

  • The standard practice is for an embryologist to look at all the embryos under a microscope and pick the one that looks the prettiest. I am not kidding. The embryologist will rank the embryos from best to worst based on their "morphology", which accounts for factors like their rotational symmetry and whether or not they have a dark and rough colored appearance. To be fair to the embryologists, this method IS better than just randomly picking an embryo; embryos with particularly bad morphology gradings do actually have a lower chance of resulting in a live birth. And for a long time, there was simply no other option But times have changed and we can now select embryos by DNA rather than simply the appearance of their cells under a microscope.
  • The main benefit of PGT-P is identifying risk outliers – individuals with unusually high disease risk. These outliers can be detected among sibling IVF embryos using polygenic scores, with particularly beneficial risk reduction for families with a history of specific disease conditions.
  • It would be morally wrong to hinder IVF families access to new technology that improves the chances for their children to have healthy lives.
  • However, the development of a technology of in vitro gametogenesis would also make possible other technological interventions into human reproduction, which as yet have barely been discussed at all. In particular, it might allow what I will call “in vitro eugenics”: the deliberate breeding of human beings in vitro by fusing sperm and egg derived from different stem-cell lines to create an embryo and then deriving new gametes from stem cells derived from that embryo, which in turn might be used in the creation of another embryo. Repeated iterations of this process would allow scientists to proceed through multiple human generations ‘in the lab’. [...] More controversially, it might also function as a powerful technology of ‘human enhancement’ by allowing researchers to use all the techniques of selective breeding to produce human individuals with a desired genotype.
  • "Chesterton's Post" is a call for action: Sometimes we need to intervene just to preserve what we already have. This separation is jarring. Polygenic screening has obvious benefits, like boosting the chance that our children will have healthy and happy lives. But there are also potential costs. The hard part is trying to sort out when skepticism about new technologies like polygenic screening reflects a mere psychological prejudice, such as status quo bias, and when it might be justified. [...] In the realm of reproduction, Chesterton’s fence reminds us that we should be wary of making sweeping changes in the genome without understanding what might go wrong.
  • Still, the distinction between embryo selection and gene editing is not as stark as it might seem. Genes mutate all the time; indeed, mutation drives evolution. If random mutations are a constant part of nature, there’s nothing intrinsically wrong with altered genes. Eventually, a combination of embryo selection and gene editing may be essential just to stay where we are now. This is because the modern world has been quietly fostering the accumulation of deleterious mutations in all of us. Genetic mutations occur throughout our lives, and some are passed along to our children. Most mutations are either neutral or harmful from the standpoint of fitness. [...] [E]ntropy is a pervasive miasma that leads to disintegration and decay. In the absence of purifying selection, and in the presence of the modern welfare state, which protects us from the ravages of disease and famine and scarcity, we will likely experience a rise in deleterious mutations, along with other genetic pathologies. [...] We may need to keep repairing the post just to preserve the parts of it that we cherish.

See also

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