Female sperm is a term that refers to a sperm that contains an X chromosome, produced in the usual way by a male, referring to the fact that, when such a sperm fertilizes an egg, a female child is born.
However, for over 20 years, dating back to the late 1980s, scientists have explored how to produce sperm whereby all of the chromosomes come from an adult woman. In the late 1990s, the theory became a partial reality when scientists developed chicken female sperm, by injecting bone marrow stem cells from a female chicken into a rooster’s testicles. This technique proved to fall below expectations, however, and has not yet been successfully adapted for use on humans.
Creating female sperm was first raised as a possibility in a patent filed in 1991 by injecting a woman’s cells into a man’s testicles, though the patent focused mostly on injecting altered male cells into a man’s testicles to correct genetic diseases.
One potential roadblock to injecting a woman’s cells into a man’s testicles is that the man’s immune system might attack and destroy the woman’s cells. In usual circumstances, when foreign cells – such as cells or organs from other people, or infectious bacteria – are injected into the human body, the immune system will reject such cells. However, a special property of a man’s testicles is that they are immune-privileged, that is, a man’s immune system will not attack foreign cells – such as a woman’s cells – injected into the sperm-producing part of the testicles. Thus, a woman’s cells will remain in the man’s testicles long enough to be converted into sperm.
Scientists have discovered a method of creating partly developed sperm cells, otherwise known as spermatogonial stem cells, from the bone marrow of both sexes, entirely in-vitro, and is seeking funding to see whether such techniques can be used to make female sperm.
If created, a female sperm cell could fertilize an egg cell, a procedure that, among other potential applications, might enable female same-sex couples to produce a child that would be the biological offspring of its two mothers. It is also claimed that production of female sperm may stimulate a female to be both the mother as well father – similar to asexual reproduction – of an offspring produced by her own sperm even though many queries both ethical as well as moral may arise on these arguments.
Given the importance of procreation to critics of same-sex marriage, the development of human female sperm and children so born may alter the debate.