Doctors don't know enough to safely use the reproductive technology they have, a doctor and an ethicist agreed Tuesday.
Jeff Kahn, a professor of bioethics at Johns Hopkins, and Dr. Randle Corfman, a leading infertility specialist in Minnesota, said on The Daily Circuit that the available technology had outpaced both scientific research and ethical consideration.
"As a physician, I'm quite nervous about this technology and what its uses could be, what the repercussions could be, in that we don't have safety studies on this," Corfman said.
He and Kahn were addressing a technique that can result in the birth of a child with genetic material from three different parents. The method could be useful if the original mother had a defect in her DNA.
"You could take the nucleus from a donor's egg and insert the genetics from the man and the woman into that cell and then get rid of the genetic abnormalities within the mitochondrial portion of that DNA," Corfman explained. "Ninety-nine-point-eight percent of the DNA in that embryo will be derived from the DNA of the mom — or it depends, if the mom and the father have combined their genetic information before this transfer has happened — and 0.2 percent then comes from the third party, from the egg donor, so to speak."
Corfman said the technology involved in the technique "is here. To do this is no big deal," he said. "We could be doing this today, if we chose to do it, in our lab. We just choose not to do it."
Kahn cautioned that such genetic transfers would mean "changing the genetics in a way that will be heritable. Whatever happens with this embryo, if it's implanted and it results in a baby, that baby can then pass on that combination of genetics if he or she reproduces."
"Anything that happens at the genetic level in the technologies that we're discussing could be passed on to the next generation," he said. "What makes this particular technology more ripe for that is that we're doing genetic modification at the level of the embryo. So that's going to be passed on in the successive generations from that child."
The lack of safety studies or any effective regulation results partly from federal policies that keep research involving human embryos at arm's length.
"There's a whole list of reproductive technologies that follow the same sort of path, where there haven't been the kind of animal model testing that we would expect in other areas of medicine," Kahn said. "Partly that's a function of the fact that our federal government has refused to fund this sort of research. It's an interesting byproduct of a decision that was made back in the mid-1980s that bans the use of federal dollars for any research that involves human embryos, effectively. It's one of these unintended consequences of a decision that was made legislatively at the federal level, related to abortion politics."
Corfman said the new technology takes him and his colleagues into realms that they had not imagined when they began their practice.
"We're infertility specialists," he said. "We help couples that are having difficulty having children. When I started out in this field 25 years ago, that's really what it was. We weren't doing pre-implantation genetic diagnosis. We weren't even considering this sort of intervention. We were just trying to help people have babies who were having trouble having babies. The technology has moved so quickly based upon the great advances that have been made in medicine and in laboratory medicine, so we can make these sorts of things happen."
Although they can make it happen, they can't make sure it is safe.
"I think we just don't know, and that's a worrisome thing," Kahn said. "When we say we just don't know what the effects are of the mitochondria, and what might happen when you combine the mitochondria from one person with the nuclear DNA from two other people, that's just worrisome. We don't know enough, I think, to say with confidence that this will be safe. ... Somebody's going to have to be first. Whether we do lots of animal model testing or not, there's always going to be a first human."
He asked, "How do we know when it's acceptable to do it, not just for the first time in humans, but creating a human this way?"
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There are even bigger concerns, which start with whether the technique is safe for the resulting infant, and whether by trying to fix one problem, scientists may inadvertently introduce mistakes into the human genetic code.
"If mistakes are made, they won't just be mistakes in the child that is born. But if that child [is a girl and] has children down the line, those children will inherit the mitochondria from that child, and we'll have introduced new genetic diseases into the human population," says Ronald Green, a bioethicist at Dartmouth College.