It’s Official: No More Crispr Babies—for Now

Last week in London, a small group of protestors braved it out in the rain in front of the Francis Crick Institute, where the Third International Summit on Human Genome Editing was taking place. The sparse congregation, from the group Stop Designer Babies, brandished signs urging “Never Again to Eugenics” and “NO HGM”(no human genetic modification). The group campaigns against what it sees as the scientific community’s lurch towards using gene editing for biological enhancement—to tweak genomes to give, say, higher intelligence or blue eyes. If this came to pass, it would be a slippery slope towards eugenics, the group argues.

Three days later, at the close of the summit, it seems the group’s wishes may have been partially granted—at least for the time being.  

After several days of experts chewing on the scientific, ethical, and governance issues associated with human genome editing, the summit’s organizing committee put out its closing statement. Heritable human genome editing—editing embryos that are then implanted to establish a pregnancy, which can pass on their edited DNA—“remains unacceptable at this time,” the committee concluded. “Public discussions and policy debates continue and are important for resolving whether this technology should be used.” 

The use of the word “whether” in that last sentence was carefully selected and carries a lot of weight, says Françoise Baylis, a bioethicist who was on the organizing committee. Crucially, the word isn’t “how”—“that, I think, is a clear signal to say the debate’s open,” she says. 

This marks a shift in attitude since the close of the last summit, in 2018, during which  Chinese scientist He Jiankui dropped a bombshell: He revealed that he had previously used Crispr to edit human embryos, resulting in the birth of three Crispr-edited babies—much to the horror of the summit’s attendees and the rest of the world. In its closing statement, the committee condemned He Jiankui’s premature actions, but at the same time it signaled a yellow rather than red light on germline genome editing—meaning, proceed with caution. It recommended setting up a “translational pathway” that could bring the approach to clinical trials in a rigorous, responsible way. 

In the intervening half a decade or so, research has confirmed that germline genome editing is still way too risky—and that’s before even beginning to grapple with the massive ethical concerns and societal ramifications. And these concerns were only compounded at this year’s summit. 

These include, for example, mosaicism, where genome editing results in some cells getting different edits to others. At the summit, Shoukhrat Mitalipov, a biologist at Oregon Health and Science University, presented findings from his lab that showed that germline genome editing had resulted in unintended—and potentially dangerous—tweaks to the genomes of embryos, which standard DNA-reading tests used to screen embryos before implantation might not pick up. Another scientist, Dagan Wells, a reproductive biologist at the University of Oxford, presented research that looked at how embryos repair breaks in their DNA after having been edited. His work found that about two-fifths of the embryos failed to repair the broken DNA. A child that grows from such an embryo could suffer health problems.

The message was loud and clear: Scientists don’t yet know how to safely edit embryos.  

To Katie Hasson, associate director of the Center for Genetics and Society, a California nonprofit that advocates for a broad prohibition of heritable genome editing, those few lines in the committee’s closing statement were the most important thing to come out of the summit. “I think this is an important step back from the brink.”

But figuring out “whether” heritable germline editing will ever be acceptable requires a lot more work. “That conversation about whether we should do it or not needs to be much broader than what we saw at the summit,” says Hasson. The world needs to reach broad societal consensus on this question, Baylis says. She worries that that work won’t happen. Up until now, these summits have led the discussion on where the field goes, but it’s still up in the air whether a fourth summit will ever take place. “I think we haven’t yet had the tough conversations that we still need to have,” says Baylis.