Before revision: Female sperm production 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 testes (to correct genetic diseases).
After revision: Female sperm production URL Patent Office|title=Repopulation of testicular Seminiferous tubules with foreign cells, corresponding resultant germ cells, and corresponding resultant animals and progeny|access-date=2013-11-09</ref> 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 testes (to correct genetic diseases).