Japanese scientists pioneer potential breakthrough for infertility : Shots

Katsuhiko Hayashi, a developmental geneticist at Osaka University, is working on ways to make what he calls “artificial” eggs and sperm from any cell in the human body.

Kosuke Okahara/Kosuke Okahara for NPR

Katsuhiko Hayashi pulls a clear plastic dish from an incubator and slides it under a microscope.

“You really want to see the actual cells, right?” Hayashi asks as he motions toward the microscope.

Hayashi, a developmental geneticist at Osaka University in Japan, is a pioneer in one of the most exciting — and controversial — fields of biomedical research: in vitro gametogenesis, or IVG.

The goal of IVG is to make unlimited supplies of what Hayashi calls “artificial” eggs and sperm from any cell in the human body. That could let anyone — older, infertile, single, gay, trans — have their own genetically related babies. Besides the technical challenges that remain to be overcome, there are deep ethical concerns about how IVG might eventually be used.

To provide a sense of how close IVG may be to becoming a reality, Hayashi and one of his colleagues in Japan recently agreed to let NPR visit their labs to talk about their research.

“Applying this kind of technology to the human is really important,” Hayashi says. “I really, really get excited about that.”

From mice to humans

Through the microscope, the cells in Hayashi’s dish look like shimmering silver blobs. They’re a type of stem cell known as induced pluripotent stem cells, or iPS.

“[The] iPS cells actually form a kind of island — they grow while touching each other,” Hayashi says. “So they look like an island.”

IPS cells can be made from any cell in the body and then theoretically can morph into any…