It's ethically OK to investigate mitochondrial replacement in humans so long as certain safeguards are in place, according a US National Academies of Sciences, Engineering, and Medicine report.
The UK recently green-lighted such 'three-person embryos' in the clinic, in which nuclear DNA from the mother's oocytes or zygotes are transferred into egg cells lacking nuclear DNA from another woman. That way, women with or with a family history of mitochondrial disease can have biological children without passing on a debilitating disease.
As a trio from the National Academies and Johns Hopkins notes in Science, the US Food and Drug Administration also began looking into the technique and tasked the Institute of Medicine with pulling together experts to weigh its ethical considerations. This committee has now issued a 164-page report.
In it, the IOM committee makes six recommendations. Namely, it says that initial clinical investigations should be limited to women at risk of passing on serious mitochondrial disease, limited to male embryos, and adhere to ethical standards developed for the use of human embryos in research, among other considerations.
A restriction to male embryos, ScienceInsider adds, would limit the risk to future generations, as men don't pass their mitochondria on.
"This is the first time it will happen in humans. We don't know how it will work," committee chairperson Jeffrey Kahn from Johns Hopkins tells ScienceInsider. "We thought it only prudent to make sure it will only affect the individual born and not future generations."
That restriction, he notes, is temporary. As more research is gathered to determine whether the technique is safe, it could be opened up to female embryos as well.
Either way, NPR notes that federal regulations currently prohibit such an approach. In a statement FDA says that it is prohibited "from using funds to review applications in which a human embryo is intentionally created or modified to include" changes that might be passed on to future generations.
Critics of the approach, though, say that it could lead to genetically modified humans. "The possibility of what you could call 'mission creep' is very real," Marcy Darnovsky, executive director of the Center for Genetics and Society, tells NPR. "People are talking about going forward not just with this but with the kind of genetic engineering that will produce outright genetically modified human beings."