Scientists could be allowed to make modifications in human DNA that can be passed down through subsequent generations, the National Academy of Sciences and the National Academy of Medicine say.
Such a groundbreaking step should only be considered after more research and then only be conducted under tight restrictions, the academies write in a highly anticipated report released Tuesday. Such work should be reserved to prevent serious diseases and disabilities, it says.
The academies determined that new gene-editing techniques had made it reasonable to pursue such controversial experiments down the road, though not quite yet.
"It is not ready now, but it might be safe enough to try in the future," R. Alta Charo, a bioethicist at the University of Wisconsin-Madison who co-chaired the committee, said. "And if certain conditions are met, it might be permissible to try it."
That conclusion counters a long-standing taboo on making changes in genes in human sperm, eggs or embryos because such alterations would be inherited by future generations. That taboo has been in place partly because of fears that mistakes could inadvertently create new diseases, which could then become a permanent part of the human gene pool.
Another concern is that this kind of genetic engineering could be used to make genetic modifications for nonmedical reasons.
For example, scientists could theoretically try to create designer babies, in which parents attempt to select the traits of their children to make them smarter, taller, better athletes or to have other supposedly superior attributes.
Nothing like that is currently possible. But even the prospect raises fears about scientists essentially changing the course of evolution and creating people who are considered genetically superior, conjuring up the kind of dystopian future described in movies and books like Aldous Huxley's Brave New World.
"These kinds of scenarios used to be science fiction; they used to be seen as far-off hypotheticals," says Marcy Darnovsky, who runs the Center for Genetics and Society, a genetic watchdog group. "But actually, right now, I think they're urgent social justice questions."
She says, "we're going to be creating a world in which the already privileged and affluent can use these high-tech procedures to make children who either have some biological advantages" or are perceived to have biological advantages. "And the scenario that plays out is not a pretty one."
But Charo says the report clearly states that any attempt to create babies from sperm, eggs or embryos that have had their DNA edited could only be tried someday under very tightly controlled conditions and only to prevent devastating medical disorders.
"We said, 'Use it for serious diseases and serious conditions only — period,'" Charo says. "We simply said, 'No enhancement.' "
But Darnovsky is skeptical that line will hold. "I don't think there's any way to keep that genie in the bottle," he says.
The report, however, was praised by many scientists.
"It's important to be extraordinarily cautious on technologies that could leave a permanent mark on the human population for all generations to come," says Eric Lander, who runs the Broad Institute at the Massachusetts Institute of Technology and Harvard University. "But it's important to try to help people. I think they've been very thoughtful about how you should balance those things."
The report acknowledges that it may be difficult in the future to draw a line between using gene-editing to prevent or treat disease and using it for enhancement. Gene-editing designed to prevent or treat the muscle disease muscular dystrophy, for example, could theoretically be used to try to make healthy people stronger.
Prominent Harvard geneticist George Church agrees. "The report is very clearly broad," he says. "It could include a lot of things people consider enhancement. I think it will be case by case and there will be some people will be consider enhancement that some people will consider preventive medicine."
For example, if scientists figure out how to makes changes that boost thinking abilities to stave off dementia in Alzheimer's patients by making them slightly above average or considerably above average, he says, "that might be considered enhancement or it might be considered preventive medicine."
Scientists have been able to edit the DNA in the cells of humans and other creatures for decades. But the academies commissioned the report after scientists developed powerful new gene-editing techniques in recent years, such as CRISPR-Cas9, that make it much easier and faster.
That raised the possibility that gene editing might be used to treat many diseases and possibly even to prevent many devastating disorders from occurring in the first place by editing out genetic mutations in sperm, eggs and embryos. That could potentially prevent a wide range of diseases, including breast cancer, Tay-Sachs, sickle cell anemia, cystic fibrosis and Huntington's disease.
As a result, the academies assembled a 21-member committee of scientists, bioethicists, lawyers, patient advocates, biotech entrepreneurs and others to conduct a far-reaching investigation that involved more than year of study.
The resulting report stresses that because the technology is so new, it would be unsafe for anyone to even begin studies to try to create babies from sperm, eggs or embryos that have had their DNA edited before conducting much more research.
The committee also says no clinical trials of gene editing should be allow unless:
"It would be essential for this research to be approached with caution, and for it to proceed with broad public input," the 261-page report states.
The report notes that the Food and Drug Administration is barred from reviewing "research in which a human embryo is intentionally created or modified to include a heritable genetic modification." Federal funding of such research is also prohibited.
Many other countries have signed an international convention prohibiting this kind of gene editing.
But the report aims to provide guidance for those countries where it's not prohibited or in those where the prohibitions would be lifted. The FDA ban, for example, could expire or be reversed.