Scientists in China have bred healthy mice from same-sex parents for the first time.
Researchers achieved the feat by altering stem cells from a female mouse and injecting them into the eggs of another female.
They also bred "somewhat unhealthy" offspring from two male mice, but the pups died shortly after birth.
The breakthrough marks the first time researchers have been able to overcome the barriers that prevent same-sex mammals from producing healthy babies.
Mice have reportedly been born from same-sex parents before but they had serious abnormalities.
The process used at the Chinese Academy of Sciences involved "substantial genetic modification" meaning it is "unlikely to be useful in humans for now".
The mice born from two mothers have now grown into adults and have had healthy offspring of their own via normal intercourse with a male.