Scientists Question Safety Of Genetically Altering Human Eggs

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A government panel has been debating whether to allow a controversial experiment involving genetic changes to women's eggs. The intention is to help women have healthy babies who might not otherwise be able to do so. But some experts are concerned about the ethics and safety of altering DNA.

NPR's Rob Stein joins us now to explain. And, Rob, to start, what exactly scientists are proposing to do here and why? I mean, what's the goal?

ROB STEIN, BYLINE: Researchers want to make changes in a very specific kind of DNA in a woman's egg. It's called mitochondrial DNA. And some women have errors in this DNA that puts them at risk for having babies with what can be very terrible genetic disorders. So one reason is to let these women try to have healthy babies. The other reason is to help women suffering from infertility.

CORNISH: So how would they go about doing this?

STEIN: Well, scientists have basically figured out how to do mitochondrial DNA transplants. What they do is they ask women with healthy mitochondrial DNA to donate some of their eggs. Then, in the laboratory, they create eggs that mostly have the genes of the woman who want to have a healthy baby, except for the defective mitochondrial DNA - which is only about 37 genes. That's replaced with the healthy mitochondrial DNA from the donated eggs.

Then they basically do standard IVF - they fertilize the egg in the laboratory and put the resulting embryos in the woman who wants to have a baby. And this seems like it could work. Scientists in Oregon, for example, have been able to breed monkeys this way that appear to be healthy, at least so far. And they've even been able make healthy human embryos. What they want to do next is take the next step and try to make healthy human babies this way.

CORNISH: And, of course, this brings about the controversy, right? I mean, what exactly are people worried about?

STEIN: Yeah, there are a lot of concerns about this. One that's got a lot of attention is that any babies made this way would technically have three genetic parents. They'd have DNA from the father's sperm, from the mother's egg, and from the woman who donated the healthy mitochondrial DNA. But there're other worries, too. One is really whether we're ready to try, whether it's safe and whether the babies might end up causing other problems in any babies, because of trying to mess around with the DNA and the egg.

And the other concern is really a really big one, is this for the first time would be making genetic changes that could be passed down through generations. And that's always been a big taboo in science. And the reason for that is if you make any mistakes, you could be introducing genetic errors into the human gene pool that would then be passed down for generations.

And then there are some other concerns that are in some ways even more disturbing. There's sort of this concern that this could open the door to a kind of futuristic "Brave New World" situation, where you'd be able to use similar techniques to pick and choose the traits of your baby, to make a baby that's tall or strong or smart or good at music. This is what people call designer babies.

CORNISH: Rob, you followed this FDA panel that's been looking at this for the last couple of days. What's come out of those discussions?

STEIN: Well, the panel spent all day yesterday and all this morning sifting through a lot of really technical scientific information and wrestling with these really tough issues. And they heard from the scientists who want to do this and they made their case. And they also heard from the opponents who are really opposed to it because they're worried about opening the door to the sort of "Gattaca" future that they talk about.

And the panel, in the end, didn't take a formal up or down vote about whether to recommend the FDA let these experiments go ahead. But they expressed a lot of worries that there just hadn't been enough basic research done in the laboratory to know whether it would be safe, both for the mothers and for any babies born this way. And they said they'd like to see a lot more research done on animals and on eggs and embryos in the laboratory before taking the next step.

That said, they sort of walked through the details of how these scientists could potentially try to do some of these experiment, although they made it clear that it would be really difficult to do, both ethically and from a safety standpoint.

CORNISH: So what happens now? I mean, could scientists actually be trying these techniques out any time soon?

STEIN: Well, it's really up to the FDA to decide what do to. And at this point, the FDA, the agency really isn't saying what they're going to do or when they may make a decision. But I think it's interesting to note that the British government is considering the exact same thing. And it looks like there's a possibility they may let it go forward, even though it's extremely controversial in that country, as well.

CORNISH: That's NPR's Rob Stein. Rob, thanks so much.

STEIN: Oh, thanks for having me. Transcript provided by NPR, Copyright NPR.