Healthy mice born from same-sex parents for first time

A healthy adult “bimaternal” mouse

A healthy adult “bimaternal” mouse

The researchers also produced mice with two dads, but the pups only survived a few days. "We have made several findings in the past by combining reproduction and regeneration, so we tried to find out whether more normal mice with two female parents, or even mice with two male parents, could be produced using haploid embryonic stem cells with gene deletions", says co-senior author Qi Zhou.

"Most people accept that genetically engineering humans is morally unconscionable, and doing the same thing to mice using stem-cell technology is just as reprehensible - it will not solve reproductive problems but will lead to misery for intelligent, sensitive beings".

"We were interested in the question of why mammals can only undergo sexual reproduction".

While some reptiles, amphibians, and fish can reproduce with one parent of the same sex, it's challenging for mammals to do the same even with the help of fertilization technology. The scientists removed three imprinted regions from the DNA of a female ESC and injected them into the egg of a female partner to produce offspring from two moms. In mammals, because certain maternal or paternal genes are shut off during germline development by a mechanism called genomic imprinting, offspring that don't receive genetic material from both a mother and a father might experience developmental abnormalities or might not be viable. By deleting these imprinted genes from immature eggs, researchers have produced bimaternal mice-mice with two mothers-in the past.

A healthy adult "bimaternal" mouse. This way their progeny only have one active copy of an imprinted gene.

They also deleted a number of "imprinted" genes from these cells, since such genes normally depend on being paired with a corresponding male gene to work properly.

They produced 29 live mice from 210 embryos, with the animals living to adulthood and having offspring of their own. About 14 percent of the pups survived, grew to adulthood and were fertile, the scientists report.

He said, "To consider exploring similar technology for human application in the near future is implausible".

Right now, it's far too complicated, and not all of the offspring survived.

The researchers aren't entirely sure why this happened, although they are planning to develop their procedures and try again in the future.

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. "We saw that the defects in bimaternal mice can be eliminated and that bipaternal reproduction barriers in mammals can also be crossed through imprinting modification".