Birds do it, bees do it—even laboratory mice do it. But with science in the mix, actually creating new life may not always require a male and a female.

Using gene editing and stem cells, researchers in China have helped mice of the same sex bear pups. While this feat has been accomplished before with mouse moms, the new study marks the first time that pups from pairs of male mice were also carried to full term.

The technology is far from ready for the leap to humans. Though mice pups born from two females appeared healthy and bore their own young, pups with two papas died soon after birth. Of the 12 born, just two survived more than 48 hours.

Still,