Never has a major scientific breakthrough carried such sinister implications for mankind - specifically, for men.

“Sorry, chaps, you’re obsolete": that may as well have been the headline of an announcement that gripped the research community on Thursday, as the birth was revealed of the world’s first mammal born to two mothers.

A team at the Chinese Academy of Sciences stunned geneticists by revealing they had effectively rewritten the rules of reproduction, and in the process discovered exactly why some animals, including humans, need to have sex.

The breakthrough came in the form of 29 mice successfully born to same-sex (female) parents.

Not only were the animals born healthy, but they went on to have babies themselves.

A similar experiment using two male parents failed, however, the pups dying within days of being born.

In achieving the successful births, the researchers proved they had identified and overcome the factor that makes joint male-female involvement in reproduction essential for humans.

Commentators said the study may pave the way for single-sex humans to reproduce in the future, although not any time soon.

Mammals can produce offspring only through sexual reproduction using an female egg fertilised by male sperm.

Not all the natural world uses the same process.