Gene-Edited Babies Move Closer to Reality, But Safety Questions Linger

When Chinese scientist He Jiankui announced in 2018 that he had created the first gene-edited babies, the global scientific community responded with alarm and condemnation. His reckless experiment ended with him in prison. Yet that hasn’t stopped the momentum behind gene-edited human embryos. Biotech entrepreneur Cathy Tie, at just 30 years old, is now arguing that pursuing this technology isn’t just urgent, it’s a moral imperative.

Tie is the founder of Origin Genomics, which launched in March with plans to bring gene-edited embryos to IVF clinics. In a recent commentary published in Trends in Genetics, she’s advocating for public funding and new regulatory pathways to advance the field toward clinical use. But beneath the optimism lie persistent questions about safety, evidence standards, and whether we truly understand the long-term consequences of editing our genetic inheritance.

The Promise and the Peril

“There are cautionary tales of first human trials where there was really no flashing red light, and people died,” warns Hank Greely, a law professor and director of the Center for Law and the Biosciences at Stanford University. His warning cuts to the heart of the dilemma: germ-line gene editing modifies cells involved in reproduction, meaning any changes could be passed to future generations. That permanence is the double-edged sword.

Correct a devastating genetic mutation, and you’ve potentially eliminated suffering forever. But introduce an accidental DNA edit elsewhere, known as an off-target effect, and you’ve potentially created new health risks that descendants inherit. Those stakes explain why dozens of countries have banned this technology outright.

Currently, couples at risk of passing genetic diseases can use IVF combined with genetic screening to identify disease-free embryos before implantation. Critics argue this already-available approach makes the need for embryo editing vanishingly small. Greely puts it bluntly: gene editing would help “a fraction of a fraction of a fraction.”

But IVF is inefficient. Viable embryos are hard to produce, even for people without inherited disease risks. Take Ian Watts and Cheyenne Ziegler. They underwent three rounds of IVF to avoid passing Watts’ Charcot-Marie-Tooth disease, a degenerative neurological disorder affecting motor skills and mobility. Eggs often fail to fertilize, fertilized ones stall in development, chromosomal abnormalities are common. Adding disease screening to this gauntlet proved brutal: three rounds produced only three disease-free embryos when they hope for three or four children.

Where Safety Meets Ambition

“The choices currently available are either not having children or doing lots of IVF,” Watts says. Gene editing could change that calculus. It could also help the exceedingly rare couples where every embryo would inherit a disease mutation.

Recent technological advances fuel Tie’s optimism. In June, Columbia University researchers revealed they had edited early-stage human embryos using base editing with remarkable precision. Tie cites this work as evidence that precise editing is within reach. Learn more about CRISPR technology and its applications.

Yet the Columbia researchers themselves sounded a cautionary note. While their work demonstrated that precise genetic changes to human embryos are possible, they didn’t actually correct disease-causing mutations. Some of their editing tools also produced unwanted and inconsistent genomic changes, leading them to conclude that “undesirable consequences” meant the technology was not ready for clinical use.

That variability matters. One successful editor doesn’t guarantee another will be safe. “Each and every mutation will therefore be a new medicine,” explains Dieter Egli, who led the Columbia work. That transforms embryo editing from a single breakthrough into a potentially endless series of expensive, time-consuming regulatory challenges.

Tie acknowledges embryo editing isn’t ready for human patients yet. But she argues it’s close enough that legal and funding barriers should come down now. Federal funding for human embryo research is restricted, and the FDA is barred from considering clinical trials involving heritable genetic modifications.

Paula Amato, a professor at Oregon Health & Science University, argues that establishing safety will require rigorous lab assessment, followed by trials in nonhuman primates, studying several generations for unexpected changes. Origin currently isn’t working with animal models and has no immediate plans to do so.

Even with perfect lab performance, an implanted embryo could carry undetected off-target effects that manifest years later, after a gene-edited person has had children of their own. “You can never be sure that you did your homework,” says Shoukhrat Mitalipov, director of the Center for Embryonic Cell and Gene Therapy at OHSU. “You think that it’s safe, but you’re transferring a kind of black box.”

Watts and Ziegler say the risks of a novel technology would be worth it. Ziegler is currently 20 weeks pregnant with one of their unaffected embryos, but they’re holding onto the ones carrying Watts’ variant, hoping correction becomes possible someday. “If the choices are to discard or to give a new technology a chance,” Ziegler says, “I would lean toward giving new technology a chance.”

The real question isn’t whether gene editing will eventually arrive in clinics, but whether we’ll know when it’s truly safe to bring it there.

Source: WIRED