Positive eugenics

In Forbes, Jon Entine discusses the rise of “positive eugenics”:

Scientists offered what they considered to be a progressive solution: “positive eugenics,” which would encourage society’s healthiest citizens to have more children—the founder of Planned Parenthood, Margaret Sanger, was an eager proponent of eugenics—and more tentatively, “negative eugenics.”The “negative” wing of eugenics prevailed, however, which for the most part meant restricting the mentally ill, poor, immigrants and non-whites from propagating. It served as an inspiration and justification for Nazism and the “Final Solution,” which led to the discrediting of the entire movement.

Now, eugenics is back in vogue with a clear focus on the positive role that genetics can and is playing in medicine and health. …

[M]odern eugenics aspirations aren’t about top-down measures promoted by the Nazis or the forced sterilizations of the past, as Comfort points out. Instead of being driven by a desire to improve the species, new eugenics is being driven largely by the individual’s personal desire to be as healthy, intelligent and attractive as possible—and for our children to be so.

Entine focuses on medical interventions, such as the testing of foetuses, and hints at the ethical debates about more controversial areas such as choice of sex and genetic enhancement. While he does not go into enhancement in detail, Entine links to an interesting post at Gene Expression, where Razib asks how “positive eugenics” might  be implemented for traits such as intelligence. As a huge number of gene variants affect intelligence, genetic screening for intelligence is not an easy task. Razib argues that this will cause the initial focus to be on mutation load. If intelligence is highly vulnerable to mutations, with variation in intelligence largely due to negative mutations, reducing mutation load will probably be a long-term approach too.

Interestingly, some of the “positive eugenics” discussed by Entine does not reduce the frequency of harmful alleles in the population, but rather affects the frequency in which they express themselves in the population. For example, the incidence of Tay Sachs disease has been reduced due to screening in Jewish populations. As the disease only manifests when someone possesses both disease-related alleles, the prevention of marriage between carriers of the alleles stops their children from having the disease. But the disease-related allele can still be harmlessly present in the next generation. Further, if there were a positive effect from carrying only one of these alleles, which is suggested by the spread of the allele despite the high costs to the disease, screening could actually increase the prevalence.

Finally, as I have posted before, a positive eugenics program has been ongoing for millions of years through our selection of partners with whom we wish to have children. We are still some way from using modern technologies to shape out genetic future to the extent that sexual selection already does.

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