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.
Some female birds, reptiles, fish and amphibians are able to reproduce alone, with hammerhead sharks and Komodo dragons some of the more colourful examples.
The Chinese team set out to identify the genetic process that takes place at the point of mammalian conception that demands genes from both sexes.
They focused on a phenomenon known and “imprinting”, where for roughly 100 genes, only the copy that comes from the mother or only the copy that comes from the father ever becomes “switched on”.
In human embryos, the male genes make up for the females ones that are not switched on and visa versa.
It means an embryo made up of same-sex genes will effectively have some missing.
To overcome this barrier, the scientists obtained some embryonic stem cells from a female mouse and used the gene-editing Crispr-Cas9, which has been likened to a genetic pair of scissors, and were able to remove maternal imprinting by “snipping” out a single letter of genetic code from three crucial regions.