Researchers are also studying how mammals would go about reproducing by parthenogenesis. So far, researchers have birthed mice spawned from two mothers (in 2004) or two fathers (2010) by uniting the genetic material of egg with egg or sperm with sperm. The tricky part was convincing the egg that when it fuses with another egg, this complimentary set of DNA (which would normally be provided by the male's sperm) actually does came from a male instead of a second egg, by "imprinting" it with modifications normally found in sperm DNA. This isn't really asexual reproduction, as the offspring has DNA from two parents, but it is interesting and strange nonetheless.

While getting mammals to undergo true asexual reproduction has thus far been beyond the power of science, researchers are trying to figure out why the union of sperm and egg is so important in mammalian reproduction, when all other domains of life have the ability to reproduce without sex. By using the techniques they develop, they might be able to produce embryonic stem cells from eggs alone, without the need for fertilization and all the moral quandaries that come with it.