When the Chinese scientist He Jiankui announced in 2018 that he had created the first gene-edited babies, the experiment was widely condemned as reckless and premature. It ended with He in prison.
But that hasn’t stopped the push for gene-edited human embryos, with biotech entrepreneur Cathy Tie arguing that doing so isn’t just urgent—it’s a “moral imperative.”
Tie is the 30-year-old founder of Origin Genomics, a company that launched in March with plans to bring gene-edited embryos to IVF clinics. In a new commentary published in the journal Trends in Genetics, she argues for public funding and new regulatory pathways to advance gene-edited babies and eventually move into clinical use.
But questions remain about what evidence researchers will need to determine whether gene-edited embryos are safe enough to attempt a human pregnancy—and what risks might remain for the resulting children.
“There are cautionary tales of first human trials where there was really no flashing red light, and people died,” says Hank Greely, a law professor and director of the Center for Law and the Biosciences at Stanford University.
So-called germ-line gene editing involves modifying cells involved in human reproduction, like embryos. Any changes made could be passed on to future generations. That could mean, for example, correcting a devastating genetic mutation for good. But accidental DNA edits elsewhere, known as “off-target effects,” could introduce new health risks that could also be passed down. Those high stakes are part of why dozens of countries have banned gene-editing of human embryos intended for pregnancy.
People at risk of passing a genetic disease on to their children can use IVF combined with genetic screening to identify disease-free embryos before transfer to the womb. Critics of embryo editing argue that screening tools make the need for it very small. Gene-editing embryos, Greely says, would be helping “a fraction of a fraction of a fraction.”
The drawback of the current approach is that IVF is inefficient; viable embryos can be hard to come by, even for people without an inherited disease risk. Ian Watts and Cheyenne Ziegler, for example, underwent three rounds of IVF in their attempt to have children that do not carry the genetic variant responsible for Watts’ Charcot-Marie-Tooth disease, a degenerative neurological disorder that impacts fine motor skills and mobility. With any IVF cycle, eggs regularly don’t fertilize, and those that do often stall in development or have chromosomal abnormalities. Adding additional screening for disease means that some viable embryos also don’t make the cut.
In Watts and Ziegler’s case, three rounds of IVF have produced eight chromosomally normal embryos, but only three without Watts’ variant. Those three embryos are likely not enough to give the couple the three or four children they hope to have one day.
“The choices currently available are either not having children or doing lots of IVF,” says Watts, a 36-year-old engineer in Long Beach, California. Gene editing could give people like him more chances at a future family. It could also help couples in the extremely rare situation where every embryo would inherit a disease-causing mutation, such as partners who each have two copies of a harmful variant.
“We’re here to treat these diseases, not just exclude embryos and call it a day,” says Tie, a former Thiel fellow who’s alluded to herself as “biotech Barbie.”
The invention of CRISPR raised the possibility of gene-edited babies more than a decade ago, and newer forms of gene editing offer increasing precision. In June, researchers at Columbia University revealed that they had edited early-stage human embryos using a technique called base editing with incredible accuracy. Tie cites this work in her commentary, arguing that precision editing is now well within reach.