Same-sex in play
Is this the start of male obsolescence?
Researchers from China have bred healthy mice with two mums that went on to have normal pups of their own by altering stem cells from a female mouse and injecting them into the eggs of another.
Of 210 embryos, 29 survived.
Mice pups from two dads were also born using a similar but more complex approach, but they only survived for a couple of days.
The researchers were examining what makes it so challenging for mammals of the same sex to reproduce, and found that some of these barriers can be overcome using stem cells and targeted gene editing.
The authors noted that there are still obstacles to using these methods in other mammals.