MS. INDIRA LAKSHMANANThanks for joining us. I'm Indira Lakshmanan sitting in for Diane Rehm. An FDA advisory panel recently said that creating embryos from the DNA of three people in order to allow women with genetic abnormalities to have healthy babies is ethical. This was seen as a major hurdle in the procedure's approval process, but a ban by Congress continues to prevent research from moving forward.

MS. INDIRA LAKSHMANANJoining me in the studio to discuss the possibilities of three-parent embryos are Jeffrey Kahn, professor of bioethics and public policy at Johns Hopkins Berman Institute of Bioethics and Sarah Karlin, healthcare reporter at Politico. From an NPR studio in New York, Dieter Egli, a biomedical researcher at Columbia University and on the phone from Berkeley, California, Marcy Darnovsky of the Center for Genetics and Society.

MS. INDIRA LAKSHMANANIf you would like to join our conversation and get in on this talk about the ethics in biomedical engineering, you can call us on 1-800-433-8850. We'll be taking your comments and your questions throughout the hour. You can also send us an email at drshow@wamu.org. You can join us on Facebook or send us a tweet. Welcome to all of you. Thanks so much for joining me today.

MR. JEFFREY KAHNThank you for having us.

LAKSHMANANSo I'd like to start out by asking Sarah if you could clarify for us, as the journalist in the room, in laymen's terms, what are we actually talking about when we say three-parent babies?

MS. SARAH KARLINSo what we're talking about is taking -- essentially using a common process that people often use now called in vitro fertilization when they are having a fertility problem. But in this case, we're taking the mitochondrial DNA, which is a small amount of your DNA and it's not the DNA people normally think of when they think of what causes your personality or how you look, a lot of the traits people think of that come from their parents.

MS. SARAH KARLINThis is a small part of your DNA that just comes from your mother and they're replacing that part of your DNA with the mitochondrial DNA from another woman to ideally prevent disease or genetic mutations that may cause diseases from that DNA from occurring in the child.

LAKSHMANANAll right. And so this, as you say, is a subset of our DNA. It's not what we think of as the pairs of the chromosomes. It's actually something much smaller than that and it only travels through the mother. So it's about replacing the mother's mitochondrial DNA. This would not be the case with the father.

KARLINCorrect. So your mitochondrial DNA comes from your mother so it's passed own just from your mother versus most of the genetic traits we think of. You're getting a mixture of DNA from your father and your mother. So every time we talk about this three-parent embryo procedure, you're always talking about it involving DNA from two women and one man.

LAKSHMANANOkay. All right. Jeffrey, where do things stand right now? Are researchers allowed to create these embryos here in the U.S.?

KAHNThey're not. And the committee that you mentioned in the introduction is one that I've chaired, actually was a committee of the National Academy of Medicine commissioned by the FDA to answer what seems like a pretty straight forward question, but one that's quite complicated. And that is where it was ethically permissible for clinical investigations of these techniques to begin in the United States. And if the answer to that question was yes and we did say it was ethically permissible, then what should the conditions or principles be in place to allow that to go forward for the first clinical investigations in humans.

KAHNSo thinking about this in the way that it was just described, a new kind of reproductive technology never before done in humans, how do you think about when it's ethically permissible to go forward? And that's a really challenging question in the U.S. or really anywhere in the world context because we don't have pathways for that. It's an...

LAKSHMANANWell, you took up that challenge. You, as you say, were the chair of that FDA advisory committee. You guys ultimately concluded that, yes, it was ethically permissible. Give us the sort of thumbnail review of why you concluded that.

KAHNSo we concluded that while there are clearly ethical issues in replacement of mitochondria -- and realize the population of mitochondria in a woman's egg, which is then fertilized and creates an embryo, there are many, many, many mitochondria in that population. So unlike in the nuclear genome, the pairs that you were mentioning before, there are many hundreds of copies and so there's no editing that's done in the context of these techniques.

KAHNIt's picking up an entire population from the woman with healthy mitochondrial DNA and replacing the diseased mitochondrial population in the woman who's got this risk. So we said that raises issues, but they're different issues than would be sort of genetic modifications, if you went in and actually did a kind of editing of the nuclear genome or even of the mitochondrial genome. So...

LAKSHMANAN'Cause you're not picking and choosing. You're actually taking the entirety of that mitochondrial DNA, replacing it.

KAHNCorrect.

LAKSHMANANThe entirety of the other woman's mitochondrial DNA.

KAHNExactly. So it's sort of en bloc, right, the entire population, taking a healthy population and replacing what was an unhealthy population with that. Now, it's from a different woman so that creates some uncertainty. So the real concern, to cut to the chase of your question, is around uncertainty and risk. We've never done this before so how do we think about when it's acceptable to go forward. And the FDA knows how to answer questions like that because they deal with this all the time in pre-clinical. So before we get into humans, investigations so you get data from animals.

KAHNYou get data from bench science, in vitro. That is in the laboratory in the dish, not in a living organism. And you make judgments about whether you know enough to try it for the first time. So we thought that that could be established and then to really address the most pressing ethical concerns which we thought were around the germ line modification, the inheritability of those genetic changes, which are passed on only from mother to their female offspring because as we just heard, mitochondria are only passed on from women.

KAHNRight. So one way to blunt that concern about germ line modification is to restrict these initial investigations until we know more to male embryos only.

LAKSHMANANOkay.

KAHNBecause then, you wouldn't have that passed on to the next generation.

LAKSHMANANSo only potential baby boys, not baby girls. All right. Well, Dieter, you're part of a team at Columbia that's been doing research on this. Tell us about the need that you're trying to address here in creating these three-person embryos.

MR. DIETER EGLIAll right. So have pioneered this technique at Columbia University and the New York Stem Cell Foundation and I've been doing this manipulation myself in the laboratory. We have developed that. We have in mind the people who suffer from that disease. I mean, these are terrible diseases and children die from it. And there's little that can be done. So this can prevent tragic outcomes and that's why I completely concur with conclusion that this is a totally ethical treatment.

LAKSHMANANAll right. Well, Marcy Darnovsky, you oppose the approval of this procedure. Tell us why. What's at stake?

MS. MARCY DARNOVSKYWell, I think there's two main kinds of things at stake. One is the safety of the children who would be produced and the other are some much broader societal concerns. And I think it's really important to say that this really isn't the only way to allow women who suffer from this particular kind of mitochondrial disease to have healthy children. Every women with this kind of mitochondrial disease, which is a small subset of people who are affected by mitochondrial disease, every woman can have a healthy child by using another woman's entire egg instead of just a piece of their egg.

MS. MARCY DARNOVSKYNow this would not -- would mean that the children would be unaffected, would not suffer from mitochondrial disease, but they wouldn't be genetically related to the woman who suffers from mitochondrial disease. And that's important to some people, but that's a preference that needs to be weighed against the well being of the future child. And the committee that Jeff chaired said, actually, in its report -- and there were a lot of good cautious things in that report -- but there were also, I thought, some questionable leaps of logic.

MS. MARCY DARNOVSKYSo the report says that the priority, the highest priority should be minimizing risks to future children. But it also acknowledges that this technique, as Dieter just said, is a response to a desire by some women to have children who are not just unaffected, healthy, but also genetically related. And so, you know, we have to ask how do you weigh those two things, the risk to the child for what's really a very biologically extreme procedure, it's not a simple add-on to IVF, against the preference of the mother.

LAKSHMANANAll right.

DARNOVSKYAnd I think that's the balance.

LAKSHMANANWell, Jeff, in the brief time we have left before the break, I want to ask you to respond to that a bit because, you know, yes, it's natural. Mothers, many mothers, it's very important to them to have a child who is biologically related to them and it seems like medicine is, also scientific advance, is partly about helping people to do things that they couldn't do before. What's wrong with that?

KAHNWell, we didn't think there was much wrong with that. And Marcy and I have had these conversations both in public and in private numerous times and the committee recognized that this was, in fact, not a medical need for the individual who would be born because you're creating a person through this technique so you can't really say you're curing them. They wouldn't have been sick because they wouldn't have existed prior to this technology being employed.

KAHNBut we do many things as it relates to reproductive technology to help women and their partners and their families have genetically related children. So it's sort of an odd argument to say we should stop now. It's not important enough now when it had been before.

LAKSHMANANAnd yet, she says it's also that you don't know what could happen to those babies down the line.

KAHNAnd that has been true of reproductive technologies since the beginning of their introduction. For the first time, in this discussion, the Food and Drug Administration in our country is talking about controls on the very beginning research on these technologies. That, I think, is a big step forward.

LAKSHMANANAll right. We're going to take a short break. When we come back, we'll be listening to more of your comments and your questions about the question of three-person embryos. Is it ethically permissible? Stay with us.

LAKSHMANANWelcome back. I'm Indira Lakshmanan sitting in for Diane Rehm. This hour, we're talking about the ethics of three-person embryos with Jeffrey Kahn, professor of bioethics and public policy at Johns Hopkins Berman Institute of Bioethics and the chairman of a panel that advised the FDA on this process, saying that it should be ethically permissible. Sarah Karlin, health care reporter at Politico. Dieter Egli, an assistant professor of developmental cell biology at the Department of Pediatrics at Columbia University. And Marcy Darnovsky, executive director of the Center for Genetics and Society in California.

LAKSHMANANSo, Dieter, you, at your lab in Columbia, have been working on this very thing, as we talked about earlier. I want to ask you, what did you think of the recommendations made by this FDA advisory panel that Jeffrey chaired?

EGLIWell, I think it's wonderful to have their guidance and support. I think it's outstanding progress. I really liked the report very much. There's a few things I don't agree with. For example, you know, I've heard the term genetic modification. It's really not a genetic modification. This is -- these are genes that are inherited by women to their children. It's as simple as that. And there's no genes being modified. So I think we need to very clearly distinguish this from other technologies that can actually modify genes, like CRISPR and other, you know, things.

LAKSHMANANThat are gene editing, forms of gene editing.

EGLIYeah. Yeah.

LAKSHMANANCRISPR that you referred to.

EGLIThere's a huge difference between those two. There is no slippery slope there. There's a clear distinction between those. What this is used for is for preventing mitochondrial disease, nothing more, nothing less.

LAKSHMANANAll right. Well, how safe is it though, Dieter?

EGLIWell, that's something that's being determined. And I think that's why we are working with the FDA and figure out the most safe way to approach this. But I've also heard, you know, the mention that, no, we are doing this for the first time. Well, let me remind you that every single being that's here in the world is the first time. So there is something that we are uncertain about when a human being comes into the world, every single time. Every single person is unique. And there's no different here. And it's just as wonderful as normal reproduction would be.

LAKSHMANANAll right. Well, Marcy, Dieter makes the case that we're all sui generis, we're all unique individuals created from nothing before. And Jeffrey has made the point that reproductive technology in general, even the most basic form of IVF, was not known and people were distrustful of it at the beginning. But, you know, it's something that now we've become completely accustomed to. So given the FDA panel's advisory and their caution that you referred to, why are you still concerned about this?

DARNOVSKYWell, actually, the panel that Jeff chaired was the Institute of Medicine panel that the FDA commissioned to look at the ethical...

LAKSHMANANMm-hmm.

DARNOVSKY...policy and social considerations. The FDA put together an expert committee to look at the safety of this technique. And they met for two days back in early 2014. And the conclusion of that panel was that it -- that the safety evidence was not adequate, that we don't know enough to go ahead with this. They said that both the animal evidence that existed -- which there's some but little -- and the preclinical evidence made it clear that it was too early to move ahead and that more evidence was needed. Now, the IOM panel, their mandate, as Jeff said, was to look at the social and policy issues, not at the safety issues. And it will be the FDA that determines whether it's safe enough to go ahead.

DARNOVSKYBut I think, you know, it's true that this is not the same as gene editing. That's -- and gene editing is the kind of procedure that would affect the traits that we think of as the ones that people might be interested in controlling. That is the case.

LAKSHMANANBy which you mean intelligence or beauty or athletic prowess, those kinds of things.

DARNOVSKYYeah, intelligence or -- yeah, or the things that we could do, actually might be able to do now, like should the child have fast-twitch muscles or slow-twitch muscles, so that the child could be better in one sport rather than another. Should that child have a gene that is associated with needing less sleep? So there are things that could potentially be controlled with gene editing. This technique does not do that. That is correct. Unfortunately...

LAKSHMANANAnd to be clear, none of that happens at this point. Nobody is going in and editing genes to make some kids sleep less or twitch more or less. That's not happening.

DARNOVSKYNo. That's what's being discussed now. And that's a big, hot controversy about gene editing right now. That's a -- it's on a bit of a separate track.

LAKSHMANANAnd this is, of course, not gene editing.

DARNOVSKYThis is not gene editing. But what -- the point that I wanted to make is that it is being used as an argument for gene editing by a number of people who are enthusiastic and who seem to me to be recklessly advocating moving forward. So the idea that there's no connection on -- in the real world, on the policy level, on the public understanding level, I'm afraid that's not the case.

LAKSHMANANHmm. All right. Well, Jeffrey, how do you respond to Marcy's point that this -- she sees it as an ethical slippery slope? That if you say okay to this, why wouldn't you say okay to so-called designer babies, where you can, you know, pick and choose from column A and B of what characteristics you want? So, you know, what is your advice to the FDA on that kind of an issue?

KAHNThe work of public policy in the context of controversial, ethical issues is exactly how to do this. How do we find ways to realize the benefits of new technologies but not suffer from the harms and not suffer from sliding down the slippery slope, as it were? And so reports like the one that we just issued on behalf of the Institute of Medicine attempted to craft a way forward mitochondrial replacement techniques, nothing more. The principles that were articulated could be applied to other areas, if the safety and other features were acceptable.

KAHNNow, the other thing to say in response to Marcy about gene editing is that the National Academy of Sciences, Engineering and Medicine, of which the National Academy of Medicine is a part, is engaged now in a year-long process to discuss the science and ethics of human gene editing. And I'm actually serving on that committee as well. So we are not considering these things the same.

LAKSHMANANHmm. So two actual separate panels to determine them, look at them discretely.

KAHNExactly. And with the recognition that mitochondrial replacement is really different. Now, I would -- I won't go on here, because I know you want to talk about other things -- but I would quibble with the way Dieter suggested that mitochondrial replacement is not genetic modification. I think that that's not correct. And the committee did not agree with that articulation. We said it is genetic modification. And we could talk about that if you like. But I think that there are important distinctions here and we should stay clear of talking about the ethics of gene editing. Because that's not what mitochondrial replacement is.

LAKSHMANANBecause that is a separate issue.

KAHNThat's right.

LAKSHMANANOkay. So if we leave that to the side, on this particular case of the mitochondrial DNA replacement, at what point can we say, Jeffrey, it's safe to proceed?

KAHNYeah. That is exactly the right question. And Marcy rightly pointed out that the FDA has convened an advisory panel which deals with the science. And the committee that I chaired and my colleagues and I did not opine about whether it was safe enough to go forward yet. We said, when the FDA determines that there is sufficient data and information from that data about safety and efficacy to go forward, that we thought there could then be a discussion about the ethics. So all of the discussion about safety needs to happen first.

LAKSHMANANWell, rather, it's an important distinction you're making, that you're saying, you decide, FDA, whether it's safe first. But once you decide that, we think it's ethically okay...

KAHNCorrect.

LAKSHMANAN...to go forward with research.

KAHNCorrect. Correct. In a very cautionary, step-wise process, which is why we said, as I mentioned before, to limit those initial investigations to male embryos, get some information and results from the birth of those children, learn from that. And then have a discussion about whether it's acceptable to go forward and, if so, how? And maybe to include female embryos at that time.

LAKSHMANANAll right. Well, the tweets and emails are already coming in. Of course, you can imagine it's a very divisive or hot-button topic. We have one person tweeting us saying that you should conceptualize this as an organ transplant. The survival of that future child is impossible without it. It's not an enhancement in any way. Someone else tweets to us, a three-person embryo is nuts. Stop this nonsense. Get over yourself. Your genes aren't all that important. There are so many kids who need loving homes. I think the person is referring to adoption. Marcy.

DARNOVSKYWell, let's see. You know, I think that the committee did strike a cautionary note, appropriately. And it was cautionary not just about, you know, the -- its own mandate -- not just about the state of the safety evidence which, as Jeff says, that wasn't their job, but also about the ethics and the policy issues. And so the reason for saying, let's just make -- let's just use male embryos to initiate a pregnancy was to deal with the safety considerations around inheritable modifications that could mean that any adverse affects of this change would be passed down to every future generation.

DARNOVSKYBut, it's -- that restriction, that limitation, is temporary, as Jeff said, and also doesn't deal with the societal concerns and policy concerns about germ line modification. It is an attempt to deal with the safety issue. But, you know, this idea that we shouldn't mix the two conversations, I agree and I disagree. You know, they are very different. But they also do need to be looked at together because, in the real world, the conversations are happening together.

LAKSHMANANOkay. Dieter, you wanted to jump in.

EGLIYes. So, wonderful. So, I mean, IVF has helped millions of peoples to have healthy children. And when it was developed, doctors and scientists saw the need and they did it. They combined an egg and a sperm. And perhaps if we were talking about this like that, we would still be talking whether we can combine that egg with this sperm. Because, according to you, Jeffrey, that's also genetic modification. Very clearly, every single fertilization, every reproduction results in a genetic change. And this is simply what that is.

EGLIThere is no genetic modification according to the way that we describe it. This is misleading statement and it's simply put out there to make a wrong concept about this technology. It's a way to discredit it and I think it's just not right.

LAKSHMANANI'm Indira Lakshmanan and you're listening to "The Diane Rehm Show." Well, Jeffrey, I'd like you to take that up. Because we also have a similar website comment from someone who describes themselves as a doctor, saying, three-parent offspring is an unfortunate, misleading description that you should not be using. The majority of our genes, nearly 25,000, are contained in the nucleus. These are, of course, the genes that decide our personal characteristics, like our height and our eye color and our appearance. And this person says, however, the mitochondria contain only 37 genes, all of which are concerned with the cells' energy production and nothing at all else.

KAHNYeah. So, first, I agree. And, in fact, the committee did not use the term three-parent embryo. I think that's an unfortunate and misleading characterization. So, agreed. And I think all of us on the -- here in the studio and on the phone may agree with that as well. That's just a shorthand and I think it's an unfortunate one. However, the discussion we're having between Dieter and now this calling -- the doctor on the website, I think raises an important question. So the writer on the website is correct. Mitochondrial DNA has many fewer genes, but they are genes. And that is what we think about when we talk about genetic modification.

KAHNIf -- and Dieter can respond to this if he likes -- but one of the techniques for mitochondrial replacement requires taking the nuclear genetic material from a fertilized egg and placing it into the mitochondrial population from a donor. So you're actually starting with what is a very early-stage embryo and then picking up the genetic material from the nucleus and putting it into a new mitochondrial DNA population. That is genetic modification from the perspective of the committee. Now, it's a different kind of genetic modification than would be editing of the nuclear genome. Absolutely it's different. But I think it's also not factually correct and it's misleading in a different way to claim that it isn't somehow genetic modification.

KAHNAnd I would say, and the committee said, it's an acceptable form of genetic modification. And I think it doesn't really help the conversation to say it just isn't that. Because it's sort of hard, based on the science, to justify that claim, I think.

LAKSHMANANHmm. All right. Well, clearly, from this very panel, we have a range in views. So there's maybe a spectrum and understanding of what is genetic modification. We have a comment on the website from Paul Knoepfler, who's an associate professor at UC Davis School of Medicine. He says, my own view is that this technology is not ready for use in humans until we have more data from animal studies. But he acknowledges that others feel it is worth the risk. Dieter.

EGLII think it's a wonderful technology. And it really addresses the need for a group of patients. And I think what they should have a stronger voice in what they need and what they want. And I think the overwhelming number of patients do want this technology or are at least very interested in using it. And here we are, having people who have no stakes in this who have, you know, are not at risk of having children having that disease, and tell, we, you know, we're going to regulate this. You've got to wait. You know, maybe in 10 years you can do that, maybe later. And their life is progressing. They are in need of this now, not somewhere, somehow, unspecified in the future.

LAKSHMANANAll right. Sarah, before we go to our break, I want to ask you, you know, Dieter is talking about a procedure that would prevent a number of horrible mitochondrial diseases that cause children to die young. Are people looking for other uses for this technique as well?

KARLINI think he's correct that right now people are not looking for other uses of this technique. Though I have talked to people that say there's some speculation that mitochondrial DNA may control things related to aging, Alzheimer's, musculature. And there are concerns from people that in the future this technique could be used to alter people in a way that's not necessarily dealing with diseases that are life-threatening or curative. But that's very speculative.

LAKSHMANANSo it's sort of future thinking, not necessarily where we are now. I mean, it brings me then -- we have another comment on the website from Joey, who says, we have the technology to permanently end an entire host of genetic disease. We should seize this moment not just for ourselves but for countless generations. We've guided our own evolution for as long as people have existed. Now, we have the technology to do so systematically and with precision, more quickly than before. The ethics are clear. People have been selectively breeding themselves based on traits for our entire history. Who doesn't do this already? Jeffrey, (laugh) you're smiling.

KAHN(laugh) I'm smiling. Well, we're not exactly plants, right, where we choose the best traits and crossbreed. It would take a lot to achieve the conclusion that the caller or the writer articulates. And I don't think that's something that we're going to alter evolution anytime soon. I do want to actually come back to something that Sarah said. I do think that there's actually a much more real and practical, extended use of these technologies, which is for women of advanced maternal age. So it turns out, as one of the people on the Web pointed out, that mitochondrial DNA produces energy in the cell. And so for women who are of advanced maternal age, this could have a very big impact on their ability to bear children.

LAKSHMANANAll right. Well, that's a good point. We'll come back to it after the break. We are going to take a short break now but, when we come back, your calls and your questions. Stay with us.

LAKSHMANANWelcome back. I'm Indira Lakshmanan. I'm sitting in for Diane Rehm. This hour we're talking about the ethics of creating embryos using the mitochondrial DNA of a woman different from the main mother. So we've been told it's not gene editing. And we're talking about the uses, the possible applications of this. Now, mainly it's for mitochondrial diseases, but before we went to the break, Jeffrey Kahn, you were telling us that it was also or could be considered as a way to sort of young-ify, to sort of make the egg of an older woman more able to produce a baby. Tell us.

KAHNRight. Right, right. So it would be a way of replacing the older mitochondria in an egg of a woman of advanced maternal age with younger mitochondria from a donor. And there are some belief in the fertility community that this would actually help women of advanced maternal age be able to have genetically related children. And there are many, many more women who could take advantage of that, than there are woman who could take advantage of mitochondrial replacement for disease purposes.

KAHNAnd in the report, I should be really clear, that we made a recommendation that the FDA needs to do everything it can to prevent this sort of indication creep and off-label use of what would be a brand-new reproductive technology. So it's hard for the FDA and our system to do that. But we made a recommendation that they try very hard and use all the tools in their toolbox to do so.

LAKSHMANANAll right. Let's go to the phones. I'm going to take a call from Patrick in Hershey, Penn. Patrick, you're on the air.

PATRICKHi there. I have a comment. My son turns three today. He is...

LAKSHMANANOh, happy birthday.

PATRICKThank you. His name is Christopher, and he is a in vitro fertilization baby. He was also born prematurely, three and a half months early. So we're very grateful to have him. But my comment is that I appreciate Marcy's concern for the risks, but I also just want to say that as a parent, it's very nice to see the features and traits of my wife and myself in our baby. And just a gift that is to us. And as Jeffrey pointed out, there were risks with other reproductive technologies, and we went forward with those, and so there should be no reason why we shouldn't continue to push the envelope, per se.

LAKSHMANANAll right.

PATRICK...and...

LAKSHMANANThank you, Patrick. So we're hearing from a happy parent there who otherwise it sounds like couldn't have had his own genetic child with his wife. Marcy, what is your response to that? You've said that you're concerned about this being used off-label or it sounds like even on-label, but what do you say to a parent like that?

DARNOVSKYWell, I think people like that are in a very difficult situation, because they do have to balance the risk to a future child against their own desire for a genetically related child. And I think, you know, for the rest of us, we need to look at that. We need to look at what people say they want. But we also need to look at -- take an objective look at the risks that were running on future people, because, you know, that is part of the regulatory responsibility that we've given to certain agencies and committees in society.

LAKSHMANANWell, what specifically are the risks that you're concerned about?

DARNOVSKYWell, you know, this technology...

LAKSHMANANWhat do you think could happen down the line?

DARNOVSKYYeah, I mean, this technology that we're talking about is -- as it's been described, it's really taking apart and putting back together egg cells or very early embryos. And the techniques themselves, the micro-manipulations that occur to remove the nucleus from an egg or embryo, put it back into a different nucleated egg or embryo, these are actually the same physical techniques that are used in cloning. And there's been lots and lots of experiments with animals in cloning. And it's a risky procedure. So -- and the fact that we do not have the preclinical evidence or sufficient animal evidence in the opinion of the FDA, I think, is telling.

LAKSHMANANDieter, you wanted to jump in there.

MR. DIETER EGIYes, so, first of all, congratulations to your child. This is wonderful. And, Marcy, you're right. These patients are in a very difficult situation. It's exactly why we scientists and doctors dedicate our lives day and night to help. That's what we do. That's our job, and that's what we like doing. And we would like to be allowed to deliver those treatments. And let me just remind you, you know, every single fertilization is a risk.

MR. DIETER EGIJust, you know, if we ask ourselves, can you put that sperm and that egg together, and what the risks are, we might never have any babies. Because the risks are great. I mean, just look at me. You know, everybody has their own medical history and they might have something to do with their genes. But we take that risk because we love our children. And in this case, we would clearly be reducing the risk, not increasing it. So if we talk about risk, the risk analysis is clearly on the side of using this technique, rather than doing it another way.

LAKSHMANANAll right. Let's take a call from Kim in Pinehurst, N.C. Kim, you're on the air.

KIMHello, everyone.

LAKSHMANANHi.

KIMI think a lot of people would be very interested to know what specific diseases that this procedure could eradicate.

LAKSHMANANAll right. Great question. Dieter, can you tell us, what are the specific mitochondrial diseases that cause children to die young that you're trying to eliminate, in this case?

EGISo thank you for the question. Well, one of them is called MELAS. That causes various problems. It can cause epilepsy, can cause, you know, muscle weakness. It severely restricts the lives of those children. And eventually they can die from it. So that's one example. There are various variations of these mitochondrial diseases with different severity, different expression. And of course one will carefully select which one is the most appropriate to go for first. But it cannot be emphasized enough that these are terrible disease and create a huge burden for affected families.

LAKSHMANANDid you want to jump...

EGIAlso what...

LAKSHMANANGo ahead.

EGI...I need to say is that these diseases affect the mitochondria, so there are many other genetic diseases that this technique won't address. It's very specific to this type of disease.

LAKSHMANANAll right. Well, Dieter, tell us how -- you know, you mentioned one disease and that there are some similar to it. How many people does this affect every year? And what's the number of women that if this were to become legal, who would be eligible for this out of the, you know, millions in the U.S. who become pregnant every year?

EGII mean, there will be thousands. And we already have, you know, families who are interested in using this technique. We are in touch with them. So I think it's really, really going to go forward.

LAKSHMANANJeffrey.

KAHNSo the -- we did an analysis of the numbers, and I should say a little bit in preface of what I'm about to say, that the recommendations of the committee were that it needed to be a very severe version of a mitochondrial DNA disease, so of the sort that Dieter was just describing. It had to be without controversy that it would be passed on from the woman in question, and that the child would inherit it, okay? So that combination of features is probably in the hundreds of women per year in the United States, not even the thousands.

KAHNSo as an initial number, so mitochondrial DNA disease is very heterogeneous. It's not one disease. It's many different things. It's very hard to diagnose. And so for the kinds of initial investigations that we're talking about, it would actually be a very small number. It could be expanded once it was seen to be safe and effective, and the kinds of questions that we're talking about were answered, and that would be up to the FDA to think about going forward. But we're talking about years in the future.

LAKSHMANANAll right. Let's take a call from Mark in Dallas, Texas. Mark, you're on the air.

MARKHi. I've heard a lot of discussion about FDA approval, but I'm just wondering where else in the world, in Europe or other areas, where this might've been tried and what the results have been.

LAKSHMANANGreat question. Jeffrey, tell us all about it.

KAHNIt is a great question. So the UK is ahead of us, and everywhere else in the world actually in relation to this question. And they are among the best scientists in the world too. Dieter and his colleagues I think would be in that group as well. In the UK there was a parliamentary vote, so the way that they control and license the creation and use of human embryos is through a centralized authority, called the Human Fertilization and Embryology Authority. And that relates to the fact that they have a national health system in the UK.

KAHNAnd they decided that they needed to actually take a vote of the members of parliament about whether it could go -- they could go forward in the UK with these new mitochondria replacement techniques. That happened after much public consultation over the course of, actually, two or three years. They voted in favor of going forward. And now the HFEA is creating guidelines for the first license applications to go forward with an MRT case in the UK. And so we expect that to be coming in the next few months. And after that there could be a pregnancy sometime in the foreseeable future. So it'll happen in the UK before it happens anywhere else.

LAKSHMANANAll right. So our friends across the pond are way ahead of us on this. Marcy, why not use the experience of the British to see whether that approach could work here? Would watching what happens there address any of your concerns?

DARNOVSKYWell, we don't know yet. We'll see. But I think, again, from a policy perspective, there's some very interesting differences in the UK as in dozens of other countries around the world. Germ line modification, that is, you know, changing by gene editing or any other method, the genes that are passed on to future generations, is actually against the lawn. Because of concerns about the kind of world we could wind up in if parents are allowed to pick and choose the traits they pass on.

DARNOVSKYSo the reason that the UK parliament voted was because they had to carve out an exception to that law in order to permit these techniques. And in the United States, we don't have the equivalent policy. If we did have that equivalent policy, I think it would change in some respect the sort of social, ethical and policy considerations about these kinds of experiments, risky human experiments.

LAKSHMANANAlthough it does sound a little bit like what the committee that Jeffrey chaired recommended was, of course, do -- you know, allowing research in this specific case, not in other cases, and putting certain cautionary limits on it, such as male only embryos, not female embryos, right?

KAHNYeah, yeah, but what's interesting about the UK example is that they will allow female and male embryos under the guidance that their crafting. But they defined MRT as being germ line modification, but not genetic modification. That was their carve out, as March just describe it, which my committee did not agree with that articulation. We didn't think that that made sense, but that's how the UK...

LAKSHMANANBecause you think they're the same thing...

KAHNWell, I...

LAKSHMANAN...they're not different things.

KAHN...I think -- we thought it was genetic modification, and if it was inheritable genetic modification, it would be germ line modification.

LAKSHMANANI'm Indira Lakshmanan, and you're listening to "The Diane Rehm Show." Well, you know, a question that we're getting here on Twitter and we're also getting it by email, one person says, "Do the scientists think they're smarter than God or 5.5 billion years of evolution?" So how do you answer this question that the scientists themselves, you may be playing God? Dieter.

EGIWonderful question. Thank you. So the way evolution works is that something bad happens to get rid of mutant genes. That can be a disease, that can be death. So unfortunately there's a lot of damage in the human genome. And for that to -- evolution gets rid of that in a very hard way. It kills people. And what doctors do is to -- as their job, is to try to prevent that. So I don't think there's anything smarter about that. This is I think just simply how medicine should be, and to help people who suffer from these things.

LAKSHMANANAll right. Well, Sarah, I want you to broaden the lens for us a little bit. We've, of course, been talking about gene editing. You know, Jeffrey was making the case that this is not gene editing, but it does seem as if, as Marcy says, we're going to increasingly face these kinds of ethical decisions. Whether it's a slippery slope or not with this, I don't know, but you tell me what are some of the larger questions that we're facing.

KARLINSo I think the big -- as we were talking about CRISPR before, that technology has gotten a lot of attention in the news lately because it does make it much easier and more precise for people to edit DNA. And that's why this policy kind of debate has really come to a head here. And at the end of last year Congress passed a budget deal, and in that law there was a policy rider that essentially prevents FDA from reviewing any research or approving any clinical research that would modify a human embryo to change its genetic traits. And while I think they were thinking of CRISPR, when they passed that law, it...

LAKSHMANANMeaning the gene editing.

KARLINThe gene editing. FDA interprets this as also applying to this mitochondrial technique of three parent embryos. So I think that there's -- in the policy, political world, there's no way to kind of separate these two things at the moment.

LAKSHMANANAll right. Tough questions. In the short time we have left, let's take one last call from Laurie in Houston, Texas. We just have a short time. Go ahead.

LAURIEHi, my name is Laurie. I just wanted to let you know that our family would be a direct beneficiary of mitochondrial replacement therapy. Our son was born with a genetic MT DNA mutation called Reye Syndrome, which is a mitochondrial disease. It is progressive and it is fatal. And this is a technique or therapy that would directly benefit my family if it was approved and as it moves forward.

LAKSHMANANWell, Laurie, I'm so sorry to hear about your son's inherited syndrome, and thank you for calling. So she makes the point that for future children she could benefit or, you know, her sisters, others could benefit from this. Jeffrey.

KAHNWe, in the course of the committee's work, held a public workshop where individuals like Laurie came to share their perspective with the committee. And it's a very compelling story because these women and their families face the prospect of either having more children who suffer from the inherited mitochondrial DNA disease, or, as Marcy said before, either adoption or having egg donation. And for some women that's a very acceptable and laudable option, but for other, they really want to have a child that's related to them through their nuclear genes. And this technique would offer a way to do that.

KAHNWe should say that our FDA responds when there's a license application submitted to it. And so that's what's happening in this context. This is not coming out of a vacuum. This request is coming from people who want to help people like Laurie. And the FDA then needs to respond about whether they will consider and maybe grant a license for a technique like this or not. And that's really what's at stake in the policy conversation.

LAKSHMANANWell, I'm sure that families like Laurie's coming forward and telling their stories, because, as she said, the condition for her child is fatal, I think that that would probably have an effect on the FDA. You know, most reproductive technology was developed without oversight, but it seems like this could set a precedent for how future reproductive technology is handled. And it feels a little bit like that puts pressure on this decision.

KAHNIt absolutely does. And as Sarah mentioned, there's language in the current budget bill, but people like Laurie and others can come forward and share their views with their members of Congress to say, we don't think that what you intended in this budget bill language was to exclude people like us from seeking treatment. Maybe you did, but let's get clear, because it will prevent the FDA from going forward and reviewing, let alone approving, new reproductive technologies like mitochondrial replacement.

LAKSHMANANAll right. One last thought from a listener, Laura in Gainesville, Fla., who says she's pregnant with IVF, and isn't there a case for potential problems with any child present at any birth? So an interesting thought that Dieter made before to leave us with. I know that is someone who had a child with a very serious illness, with cancer, who was not the result of IVF. Of course something terrible can happen in any case.

LAKSHMANANAll right. We've been speaking with Jeffrey Kahn, professor at Johns Hopkins Berman Institute of Bioethics, Sarah Karlin, health care reporter at Politico, Dieter Egli of the Department of Pediatrics at Columbia University and Marcy Darnovsky, executive director of the Center of Genetics and Society. Thank you, to the four of you, for joining me this hour. Thank you to all your listeners for tuning in. I'm Indira Lakshmanan. It's "The Diane Rehm Show."