Dandelions do it all the time, aphids do it occasionally, and now mice can do it too, but only in the laboratory. Parthenogenesis — the reproduction of a gamete without fertilization — has been achieved in mice by Tomohiro Kono and colleagues, who announced the birth of live mice that were derived from two mothers but no father.

“This achievement, published in Nature, might be seen as being of comparable significance to the birth in 1996 of Dolly the sheep. And it may prove almost as controversial” (The Financial Times).

The researchers knocked out a gene in an immature mouse egg to give it a 'male-like' imprinted character, and then combined the cell's genetic material with that of a normal mature egg. “From around 600 eggs, only two live mice were born” (The Financial Times). “One mouse, named Kaguya, after a Japanese folk tale in which a princess is born from a bamboo stump, grew to adulthood and has become a mother herself — though by conventional means” (The Washington Post).

“The practical implications are obscure, since the method is even more complex, inefficient and unsafe than cloning”, said Ian Wilmut (The Daily Telegraph). But could such a 'virgin birth' occur in humans too? “Researchers were quick to head off suggestions that the technique could be used to treat infertility” (BBC News Online) or that it “makes men obsolete” (The Daily Telegraph). However, the use of the technique might “circumvent the political and ethical obstacles to using stem cells” (BBC News Online).

Whatever its application, this work is “sure to stimulate conversation about the intrinsic importance of male–female pairing, at both the biological and the social level” (The Washington Post).