We women can no longer take comfort from the fact that we'll always be necessary for the reproduction of the species: geneticists have succeeded in creating viable male and female mice from two fathers.
The achievement could be a step toward preserving endangered species, improving livestock breeds, and advancing human assisted reproductive technology. It also opens the possibility of gay male couples having their own genetic children.
In essence, the MD Anderson Cancer Center team manipulated stem cells to create 'male eggs'. They used a skin cell sample from a male mouse to create stem cells, then multiplied them over and over; about one in a hundred lost their Y chromosome.
These cells were then injected into embryos and transplanted into surrogate mothers, which gave birth to female XO/XX 'chimeras' with one X chromosome from the original male mouse fibroblast.
The female chimeras were mated with normal male mice - and some of the offspring, both male and female, had genetic contributions from two fathers.
"It is also possible that one male could produce both oocytes and sperm for self-fertilization to generate male and female progeny," the scientists point out. This technique could be valuable for preserving species when no females remain.
The team says that in future it could be perfectly possible to generate human oocytes from male stem cells in vitro. Using in vitro fertilization, this would eliminate the need for female XO/XX chimeras, although a surrogate mother would still be needed to carry the two-father pregnancy to term.
Using a variation of the technique, the researchers say: "It may also be possible to generate sperm from a female donor and produce viable male and female progeny with two mothers."
In fact, something like this has already been done: in 2004 Japanese scientists successfully created mice with two mothers. The achievement led to panic in the right-wing press - and perhaps slightly nicer behavior from men worried about being made evolutionarily redundant.
It's our turn now...