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We won’t use CRISPR to make super-smart babies—but only because we can’t

Gene experts speculate that our worst gene-editing fears won’t come true because they are too complex for us to pull them off.
January 18, 2019

One of the main worries that the public has about CRISPR is that it could be used to create “designer babies” with increased levels of intelligence. In the worst-case scenario, it could give an unfair advantage to parents who can afford to upgrade their offspring. Indeed, a Pew survey of US residents in July 2018 found their biggest worry was that CRISPR “will only be available to the wealthy.”

They needn’t worry, said three top gene-editing scientists this week. Intelligence is too complex to engineer and that’s a good thing, they say, since it “may ultimately save us from the hazards of humanity’s hubris.”

In November, the Chinese scientist He Jiankui claimed he’d secretly used the gene-editing tool to create twin girls resistant to HIV. That raised alarms because it showed there is no way to stop the manufacture of designer babies. 

But the public’s concern about the creation of intellectual elites probably isn’t realistic, according an editorial published January 16 in the New England Journal of Medicine. The article was written by George Daley, the dean of Harvard Medical School, and two European experts in embryology, Robin Lovell-Badge and Julie Steffann.

“In the long run, our greatest protection against inappropriate genome editing may be the implausibility of influencing traits such as intelligence, which emerge from complex interactions among multiple genes and environments,” they write.

We have linked more than a thousand genes to IQ or how far a person gets in school. Right now, scientists don’t know what those genes do, and what’s more, gene-editing tools aren’t yet up to the job of tailoring an embryo’s genes at so many locations.

To the editorial writers, that kind of ignorance is bliss. They are eager to see gene editing used to stamp out genetic disease in embryos—and they think it’s almost ready for the job, too.  Because serious congenital diseases like Huntington’s or cystic fibrosis are often caused by specific DNA errors in single genes, it’s quite possible to repair them with CRISPR. Doing it in an embryo, they say, might be the best way to get rid of the problem.

Daley and other scientists now want to see this sort of medicine move forward. But that will become harder if gene editing is flagrantly abused, since regulators will continue to block it and public opinion could sour.

For the twin girls, He Jiankui said he had removed a gene called CCR5 to make them immune to HIV. Even though He scored a first, Daley and his coauthors agree, it was an ignominious one because he didn’t follow ethics rules. “He will forever be remembered for his reckless flouting of widely articulated scientific, clinical, and ethical standards,” they write.

He now appears to be under house arrest—the New York Times spotted him behind bars installed on the balcony of a campus apartment—as Chinese authorities investigate, or at least allow the scandal blow over. 

The authors of today’s NEJM editorial argue strongly that this is just the beginning—there are legitimate reasons to alter embryos, they say. These include situations in which a couple can’t otherwise have healthy children or want to avoid passing on disease risk genes when trying to conceive via IVF.

One risk to these great medical ambitions is that CRISPR gets used for purposes that the public still thinks are troubling. Opinion polls show that most people are okay with using it to wipe out disease mutations. But only about 20% think using it for “enhancement”—specifically, trying to increase the intelligence of offspring—is a good idea. 

Luckily for scientists, they don’t have to tell us whether they think increasing intelligence is good or bad. It’s not possible, they say, so don’t worry about it. Just kick that can into the future. 

Deep Dive


These scientists used CRISPR to put an alligator gene into catfish

The resulting fish appear to be more resistant to disease and could improve commercial production—should they ever be approved.

Next up for CRISPR: Gene editing for the masses?

Last year, Verve Therapeutics started the first human trial of a CRISPR treatment that could benefit most people—a signal that gene editing may be ready to go mainstream.

CRISPR for high cholesterol: 10 Breakthrough Technologies 2023

New forms of the gene-editing tool could enable treatments for common diseases.

An ALS patient set a record for communicating via a brain implant: 62 words per minute

Brain interfaces could let paralyzed people speak at almost normal speeds.

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Illustration by Rose Wong

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