Four months after a Chinese scientist shocked the world with news that he had intentionally altered the DNA of twin girls, top genetics experts and ethicists are calling for a partial ban on the use of a gene-editing technology that can be used to make modified humans.
The researchers, including pioneers of the editing technique, are asking nations to prohibit doctors and scientists from changing the DNA in sperm, eggs or embryos intended to produce living children. The ban would be in place while more stringent standards for the technology were developed, and the technology, Crispr, could still be used for other research or for treating disease by editing non-reproductive cells.
"This is a crucial moment in the history of science: a new technology offers the potential to rewrite the script of human life," said Carrie Wolinetz, associate director for science policy at National Institutes of Health, and Francis Collins, who directs the agency, in a letter published alongside the proposal in the journal Nature. "Human gene editing for reproductive purposes carries very serious consequences -- social, ethical, philosophical and theological. Such great consequences deserve deep reflection."
Crispr allows scientists to alter the genome more precisely than ever before, cutting or pasting bits of genetic code as small as individual DNA letters. It's been heralded as a way to treat diseases caused by defective genes.
Because it's relatively easy to use, it has also raised fears that someone could modify genes in a way that could harm a patient, or change the genetics of an unborn child unnecessarily and with unknown consequences that would carry on in future generations. The potential slowdown in experimental progress is worth stopping misuse, the researchers said.
"The framework we are calling for will place major speed bumps in front of the most adventurous plans to re-engineer the human species," wrote the researchers. "But the risks of the alternative -- which include harming patients and eroding public trust -- are much worse."
The signers to the proposal include Eric Lander, founding director of the Broad Institute at the Massachusetts Institute of Technology and Harvard University, Emmanuelle Charpentier, director a the Max Planck Institute for Infection Biology in Berlin who is credited with co-discovering the technology and Feng Zhang, a biochemist at the Broad Institute who first used the technique in human cells.
The proposal was spurred in part by the birth in November of twin girls whose genes had been altered to make them resistant to HIV. He Jiankui, a U.S.-educated scientist based in Shenzhen, used Crispr to craft the changes, making the girls the world's first gene-edited babies despite the fact that China has regulations intended to restrict genome editing in human embryos.
While a ban backed by prominent scientists may dissuade some scientists, many countries already prohibit the practices outlined.
"In almost every country where this would likely happen, this is already illegal. That wasn't originally clear in China, but now it's clear in China, too," said Hank Greely, a bioethicist at Stanford University in California.
Greely said he would be shocked if in five years the technique is safe enough to try in human babies. "It is criminally reckless to try this in babies anytime soon."
Another prominent scientist said the calls for a prohibition are too little, too late. Jennifer Doudna, professor of biochemistry and molecular biology at the University of California, Berkeley, is also credited as an inventor of Crispr. She and other researchers called for a ban four years ago.
"We had guidelines, but we didn't have any kind of articulated consequences," she said in a telephone interview. The world needs to figure out how to "put into place very strict requirements with appropriate consequences that make it unthinkable to violate them."
That could include cutting off research funding, banning publication of the results, or blocking violators from attending prominent research conferences where breakthrough results are announced, she said.
In China, He Jiankui faced some of those sanctions. After he announced that he had modified the girls' genes, the Southern University of Science and Technology ended his research activities and fired him after a government investigation found he violated the law. It's possible he'll face further consequences from the government.
"Everyone agrees we shouldn't be doing this yet," said the Broad Institute's Lander. "There's an easy way to deal with rogue actors -- laws."