Genetic screening to improve intelligence

Writing in The Conversation, ethicist Julian Savulescu discusses recently published findings that indicate that children with two copies of a common gene (Thr92Ala) and low thyroid hormone levels apparently increase the likelihood of low IQ by a factor of four.  Since the “risk of low intelligence” depends upon both the genetic configuration and hormonal level, he suggests that such children could be treated with supplemental thyroid hormones “to enhance their intelligence.”

The “low intelligence” to which he refers is the 4 % of the U.K. population estimated to have an IQ of between 70 and 85.

“If we could enhance their intelligence, say with thyroid hormone supplementation,” he writes, “we should.”

Savulescu’s focus on intelligence in this case should not become a distraction.  Supplementing hormones seems to present no special ethical problems, since the goal in that case would not be eugenic perfectionism or enhancement, but therapeutic correction of a deficiency.  However, Savulescu goes beyond this to propose that IVF embryos be screened, and that embryos found to have two copies of the Thr92Ala gene not be selected for implantation.  What is unstated is that the ‘defective’ embryos should be killed.  This would be an ethical/moral problem for anyone who holds that deliberately killing human embryos is wrong.


One thought on “Genetic screening to improve intelligence”

  1. The approach suggested by Savulescu, and of others who may argue for eugenic enhancement, is often critiqued by reference to Aldous Huxley’s Brave New World. However, the eugenic programme described by Huxley differed in one important respect from that proposed by Savulescu (and others). Some embryos in Huxley’s hatchery die during cloning, and accidents, like earthquakes, can kill large numbers. But killing embryos is not used as a form of eugenic selection in the civilization in Brave New World. “Even Epsilons are useful,” the saying goes.

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