Scientists in Japan are at the forefront of one the most controversial areas of biomedical research: creating sperm and eggs in the laboratory from practically any cell in the body.

Transcript

STEVE INSKEEP, HOST:

Well, it's not often that we get to witness the beginnings of a scientific revolution in real time, but that's exactly what may be playing out in the world of human reproduction. And today we get an unusual peek inside that race. NPR health correspondent Rob Stein joins us now. So Rob, I'm all ears. What's this potential scientific revolution?

ROB STEIN, BYLINE: It's called in vitro gametogenesis, or IVG. Think IVF 2.0, but instead of mixing natural sperm and eggs in a test tube, IVG would make what some scientists call artificial sperm and eggs in the lab from any cell in anyone's body.

INSKEEP: OK. I'm trying to imagine this, Rob. My skin cells - what - you're saying that could become an egg or a sperm?

STEIN: That's right. That's right. Sperm and eggs that could create an embryo in the lab just like IVF. But IVG, it would render the biological clock irrelevant, helping anyone of any age have a genetically related baby - same for anyone single, gay, trans.

INSKEEP: Wow, that sounds amazing and, I can imagine, controversial.

STEIN: And we'll definitely talk about that. But first, let's meet the two scientists who essentially launched this whole field and are still on the leading edge of making IVG a reality. They're both Japanese. They live and work in Japan.

INSKEEP: And Rob, you went to go meet them?

STEIN: That's right. They both agreed to let me come visit them in their lab. So I flew to Tokyo.

Well, we just landed. It was a pretty easy flight.

And then hopped a bullet train west to Osaka. And that's where I find Professor Katsuhiko Hayashi at Osaka University.

Hi. How are you?

KATSUHIKO HAYASHI: I'm OK.

STEIN: Sorry we're a little late, got a little lost.

HAYASHI: Yeah, it's a bit complicated building.

STEIN: Hayashi is famous in scientific circles because he was the first one to make IVG look like it could really work. He leads me into his lab to show me how. Hayashi pulls a dish from an incubator and slides it under a microscope. First, Hayashi figured out how to turn skin cells from mice into mouse eggs. He motions for me to take a look.

Oh, wow. Each of those glowing blue balls is an egg.

HAYASHI: Yeah, yeah. Yes.

STEIN: There's so many of them.

HAYASHI: In one experiment, basically, we can make 4,000 eggs.

STEIN: Four thousand eggs? Like little egg factories - each one of these is a little egg factory.

HAYASHI: Kind of - egg factory in mice, at the moment.

STEIN: Then Hayashi went even further. He used the artificial mouse eggs to breed healthy baby mice, triggering an international race to do the same thing for people.

HAYASHI: Applying this kind of technology to the human is really important. I'm really, really excited about that.

STEIN: But the big question is - how soon could this happen? A California biotech startup called Conception says really soon. I visited Conception a few weeks earlier, and they claim they'll have human IVG eggs ready to try to fertilize within a year. Hayashi is skeptical.

HAYASHI: It's impossible, to my opinion. One year - I don't think so.

STEIN: That said, Hayashi says he and his colleagues are at least as close as the Americans. But to find out how close, I should visit Professor Mitinori Saitou at the University of Kyoto. When I get there, it's hot and steamy.

UNIDENTIFIED PERSON: Please come in. Can you take off your shoes and change into your slippers?

STEIN: Slippers - oh, OK. Sure, sure, sure. Hello, Professor Saitou?

MITINORI SAITOU: Yes, this is Mitinori Saitou.

STEIN: Oh, so nice to meet you. Rob Stein from NPR.

Saitou is the first - and so far only - scientist to prove he could turn human cells into very primitive human eggs.

(SOUNDBITE OF DOOR HINGE SQUEAKING)

STEIN: Saitou takes me into his lab to show me the next step.

SAITOU: And that's the culture.

STEIN: Cell culture.

SAITOU: That's the most kind of important place.

STEIN: Most important place because this is where Saitou is trying to coax his primitive human eggs into maturity.

SAITOU: For example, you know, we are trying to understand signals that instruct our cells' maturation.

STEIN: To tell the cells you should start to become an egg.

SAITOU: Yeah, exactly.

STEIN: I asked Saitou, so what does he think of the U.S. biotech's claim about trying to fertilize an egg within a year?

SAITOU: That's amazing (laughter).

STEIN: Amazing like you believe it, or amazing like you're skeptical?

SAITOU: I don't really know. You know, some sort of incredible or - how to say - a scientific breakthrough may happen. But let's see (laughter).

STEIN: Have you gotten that far?

SAITOU: We are working on that.

STEIN: Have you had any success?

SAITOU: We are working on that. That's not yet published, so I cannot tell.

STEIN: The Japanese scientists warn it would take years to show artificial embryos aren't carrying dangerous genetic mutations. But even if IVG's safe, the Japanese scientists are cautious for another reason.

SAITOU: There are so many ethical problems, so this is a thing what we have to really think about.

INSKEEP: OK. So Rob, now we're getting into the ethical concerns. What are some of those concerns?

STEIN: Well, there's a number of them. For example, IVG could not only help really anyone have genetically related babies, IVG could make traditional baby-making antiquated for everyone.

INSKEEP: Wait, wait, wait - everyone?

STEIN: Yeah. IVG clinics could start mass producing artificial embryos so parents could use only those with the healthiest genes and possibly the traits they want.

INSKEEP: Wow. That just sounds already really controversial, especially in the United States. What about Japan?

STEIN: Yeah, definitely there, too. And to talk about that, I meet with...

MISAO FUJITA: Misao Fujita.

STEIN: She's a bioethicist.

FUJITA: Professor Kyoto University.

STEIN: She says the Japanese share U.S. queasiness about mass producing human embryos.

FUJITA: Then that means maybe exploitation of embryos, commercialization of reproduction. And also you could manipulate genetic information. That means you can create designer baby. It reminds me of playing God. Yeah.

STEIN: But Japan would even be uncomfortable about creating babies outside of traditional families.

FUJITA: If you can create artificial embryos, then that means maybe a single person can create his or her own baby. So who is mother and father? So that means social confusion.

INSKEEP: Social confusion, wow. OK, interesting. Rob, what do scientists have to say about all this?

STEIN: So the Japanese scientists say they're uncomfortable with some of the implications, too. Here's Professor Saitou again.

SAITOU: Science always have good aspects and also have - I'm not sure it's bad, but negative impacts, like atomic bombs or any technological development. If you use it in a wise manner, it's always good. But everything can be used in a bad way.

STEIN: Even so, Saitou and Hayashi hope the Japanese government will support something the U.S. government would never support today - the creation of artificial embryos to help them win the race to make IVG a reality.

INSKEEP: Wow, this has been riveting. Rob, thanks very much. That's NPR health correspondent Rob Stein reporting from Japan. Rob, thanks.

STEIN: You bet.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.