Editing of human cells to alter traits handed down to future generations may one day be ethically permissible, said a committee co-chaired by bioethicist Alta Charo, a professor at the University of Wisconsin School of Law.
"It is not ready now, but it might be safe enough to try in the future," Charo told National Public Radio. "And if certain conditions are met, it might be permissible to try it."
Charo, along with UW-Madison science communication professor Dietram Scheufele, was part of a committee appointed by the National Academies of Sciences and Medicine that on Tuesday released a groundbreaking report on the ethics of human gene editing.
Despite the consensus at a 2015 international summit in Washington, D.C., where scientists concluded they should not perform gene editing on reproductive cells intended for establishing a pregnancy, the new report advises that such research might be permitted after further work to develop appropriate risk/benefit standards.
The panel recommended alteration of genes in human reproductive cells, sometimes called germ lines, be allowed only to prevent serious disease or disability for which there is no treatment. On the other hand, the potential benefits of human germ line editing to enhance desired inherited traits — like beauty, intelligence or strength — are at this time unlikely to outweigh risks like the inheritance of undesired mutations, panel members found.
“Up until now, we’ve been talking only hypothetically and most people assumed we simply wouldn’t ever do this,” Charo told Nature. “We are not saying that you have to or you should, but we are saying that if you can meet these criteria it is permissible.”
In the United States, the use of federal funds for research involving the creation of a human embryo to include an inheritable modification is prohibited. But the committee defined a set of criteria for use in other countries, or in the U.S. if restrictions were allowed to expire. The criteria include: absence of reasonable alternatives, data on the likely risks and potential health benefits; rigorous oversight; and comprehensive plans for long-term, multi-generational follow-up.
The committee also called for broad public education and engagement in applying societal values to the risks and benefits of gene editing technologies.
In the months since the Washington summit, the development of a gene-editing tool called Crispr-Cas9 has made addressing the ethical issues surrounding human gene editing urgent.
As human genome editing becomes more effective, clinicians working in countries with few regulations will likely begin modifying embryos and implanting them in patients, raising the potential for inheritance of unintended mutations along with targeted changes, Charo said.
“We are very much aware that medical tourism is a fact of global life now,” she said. “We certainly don't want to see the same thing, and a prohibition might exacerbate the problem.”
Scheufele, a social scientist who studies communication and public understanding of science, spoke to the importance of public debate on the ethical issues involved.
“We want to bring in people even if they know little about the topic and get them to the point where they can engage in meaningful debate,” Scheufele said. “We want to move forward in a responsible fashion with the best available science and a meaningful understanding of the risks and benefits.”
The report also established a set of broad governance principles with respect to human genome editing in the U.S. and elsewhere: promote well-being, transparency, due care, responsible science, respect for persons, fairness and transnational cooperation.
“Every country struggles with the same set of complexities but has a different regulatory system. So, we established larger principles that are applicable across different political or cultural contexts,” Scheufele said.
While the National Academies panel drew a bright line between gene modification for treatment of disease and gene modification for enhancement, the boundary often is not clear, say opponents of human germ line editing.
“This opens the door to advertisements from fertility clinics of giving your child the best start in life with a gene-editing packet,” Marcy Darnovsky of the Center for Genetics and Society, a public interest group in Berkeley, Calif., told the New York Times. “And whether these are real advantages or perceived advantages, they would accrue disproportionately to people who are already advantaged.”
The new guidelines, Darnovsky noted, also set the United States apart from many European countries that have signed a treaty to refrain from human germ line editing.
George Church, co-founder of the gene-editing company Editas Medicine, told Wired that the line between treatment and enhancement will be hard to hit.
“In the process of fixing something that is broken, you can move it to the middle of the bell curve or beyond,” said Church, a geneticist at Harvard and MIT. “If you are aiming at the middle, you will fall on the low or the high side.”
Church isn’t worried about athletes using Crispr-based therapies, he said the big market is aging adults who want to put off the effects of old age. “If you want to be useful longer or do age reversal, that could be preventive medicine,” he said. “But if a therapy was sufficiently good, it would be enhancement.”