This computer reconstruction of an embryo developing in the womb shows the foetus at eight weeks. PHOTO: File

It doesn’t take long for seemingly outlandish ideas to become normalized. Today, Stanford University professor Hank Greely’s assertion that Americans will stop having sex to procreate sounds absurd. But in a couple of decades, he predicts, that will be the accepted reality.

Greely, director of Stanford Law School’s Center for Law and the Biosciences, believes that we’re 20 to 30 years away from a time when most American procreation will begin by selecting from a range of embryos created with the parents’ DNA in a lab.

This already happens on a limited basis for disease prevention and occasionally sex selection, but he argues it will become far cheaper and widely available thanks to stem cell technology that will allow couples to make eggs and sperm out of stem cells from their skin.

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Prospective parents will start by screening those embryos for genetic diseases such as Huntington’s, but quickly expand to other traits, he predicts. Perhaps they’ll weed out the BRAC1 gene for breast cancer, predispositions for Alzheimers, or they’ll be able to select cosmetic features such as hair and eye color, and even more complex traits such as intelligence.

“I don’t think we’re going to be able to say this embryo will get a 1550 on its two-part SAT,” Greely said this week at Aspen Ideas Festival. “But, this embryo has a 60 per cent chance of being in the top half, this embryo has a 13 per cent chance of being in the top 10 per cent —I think that’s really possible.”

And, though he recognises that there are ethical issues, Greely views this scenario as far from dystopian. “People say, ‘How can we let this happen?’ I think we will,” he said.

At times, he sounded flippant about the prospect. “I think one of the hardest things about this will be all the divorces that come about when she wants embryo number 15 and he wants embryo number 64,” he said. “I think the decision making will be a real challenge for people. How do you weigh a slightly higher chance of diabetes with slightly lower risk of schizophrenia against better musical ability and a much lower risk of colon cancer? Good luck.”

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Greely brushed aside the concern that what he’s describing meddles too much with nature. “This is not designer babies or super babies,” he said. “This is selecting embryos. You take two people, all you can get out of a baby is what those two people have.”

There are already concerns that CRISPR, the tool that scientists use to edit DNA, will be put to use to create perfect embryos. But Greely dismisses this as unlikely. He argues that the embryo selection process will simply begin as an infertility treatment before expanding. “People, particularly where I live in Silicon Valley, will want to do it to get their perfect egg,” he added.

Greely acknowledges that ethical issues will likely arise around safety, coercion, fairness, and family structure, but does not see any of these as obstacles that will halt the development of this practice.

And what of a world where the elites have perfectly selected children while those less well off are left to deal with the diseases and imperfections that no longer affect the wealthy? Greely has the answer: The whole thing will be free. “The parents won’t be charged.”

The key is the health care cost savings, he said, pointing out that, should it cost $10,000 to make a baby this way, then 100 babies would cost $1 million dollars. Meanwhile, the cost of caring for a truly sick baby is so great, Greely said the births of just 0.3 sick babies would need to be avoided to save $1 million.

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Greely’s scenario could well prove overly optimistic in the US, and it certainly doesn’t apply internationally. “I think different cultures will pick it up at different rates. I think the US will be relatively accepting, Germany with its history is very anti any genetic interventions and I think they’re going to be slow,” said Greely.

Should his vision come to pass, wealthy nations such as the US and China could begin this practice long before Somalia, for example. And so it seems almost inevitable that the world would become genetically divided between those who can breed out the flaws, and those who cannot.

Greely foresees a scenario where future generations will be much healthier, and possibly a little taller and smarter. From his telling, this unnerving prophesy sounds almost normal — which is the most terrifying prospect of all.

This article originally appeared on Quartz.