CRISPR: gene editing made easy Ella Maru Studio/SPL

While gene editing is already saving lives, for now, the technique shouldn’t be used to edit embryos or create changes that will be passed on through the generations. So say the authors of a new report on editing the human genome.

However, such germline editing could be permitted in the future, if properly regulated and with public approval, concludes the report. It was compiled by the Committee on Human Genome Editing, a group of 22 researchers, lawyers and ethicists.

Gene therapy isn’t new, but the development of the CRISPR Cas-9 technique has made it much easier to change a genome. The technique enables researchers to specifically target a region of DNA and add or remove genes – both a useful tool for research, and a technique that can treat diseases in people.


But gene editing treatments are not without some risk. There’s a chance, for instance, that a therapy will have “off-target effects”, changing other genes. The risks will depend on the disorder and the treatment, and regulators must weigh up the risks against treatment benefits on a case-by-case basis, the authors say.

Designer babies

The risks are higher when it comes to germline editing. Beyond off-target effects, there’s a chance that attempts to perform gene editing on an embryo will create a mosaic of treated and untreated cells. “It’s the most common problem in mouse studies,” says Robin Lovell-Badge of the Francis Crick Institute in London, who co-authored the report.

Lovell-Badge and his colleagues concluded that germline editing could be performed in humans, but only after much more research to minimise the risks and weigh them up against any benefits. Even then, the public must have a say, and any trials must be performed under strict oversight.

The report is also not in favour of gene editing techniques to enhance people, or create “designer babies” – but only for the time being. “It’s the thing that worries people the most, because it is felt to be unfair,” says Lovell-Badge. “It’s the same as using drugs to cheat.”

But the boundary between treatment and enhancement is often blurred. If you were able to lower a person’s cholesterol for example, where would the cut-off be? In the future, some aspects of enhancement might be considered acceptable, says Lovell-Badge. “We may need to modify aspects of our physiology to adapt to climate change, but that’s being speculative,” he says. “We’re not saying it should never be done – but not now.”

Based on what we already know about genes and health, it might be possible to boost a person’s muscle mass, for instance, using gene editing. But for many other features – including intelligence – hundreds or thousands of genes are involved. Using gene editing to enhance these features isn’t currently feasible.

Read more: Why banning CRISPR gene editing would be unnecessarily cautious