Scientists create mice with cells from 2 males for 1st time

The pups appeared to grow normally and were able to become parents themselves in the usual way, researchers said

For the first time, scientists have created baby mice from two males.

This raises the distant possibility of using the same technique for people – although experts caution that very few mouse embryos developed into live mouse pups and no one knows whether it would work for humans.

Still, “It’s a very clever strategy," said Diana Laird, a stem cell and reproductive expert at the University of California, San Francisco, who was not involved in the research. "It’s an important step in both stem cell and reproductive biology.”

Scientists described their work in a study published Wednesday in the journal Nature.

First, they took skin cells from the tails of male mice and transformed them into “induced pluripotent stem cells,” which can develop into many different types of cells or tissues. Then, through a process that involved growing them and treating them with a drug, they converted male mouse stem cells into female cells and produced functional egg cells. Finally, they fertilized those eggs and implanted the embryos into female mice. About 1% of the embryos – 7 out of 630 – grew into live mouse pups.

The pups appeared to grow normally and were able to become parents themselves in the usual way, research leader Katsuhiko Hayashi of Kyushu University and Osaka University in Japan told fellow scientists at the Third International Summit on Human Genome Editing last week.

In a commentary published alongside the Nature study, Laird and her colleague, Jonathan Bayerl, said the work “opens up new avenues in reproductive biology and fertility research" for animals and people. Down the road, for example, it might be possible to reproduce endangered mammals from a single male.