The term sperm donor refers to a man who provides sperm to an intended recipient for reproductive purposes. Sperm donation is one form of gamete donation and may occur independently or in conjunction with egg (oocyte) donation, the other form of gamete donation. As a form of third-party reproduction, sperm donation has identity-related implications for various members of the family unit, especially for the donor and the offspring. In turn, sperm donation is often viewed as controversial and has raised a number of ethical questions since its development. This entry briefly introduces the [Page 1612]history and process of sperm donation, offers an overview of different types of sperm donors, and highlights academic knowledge and ethical concerns related to sperm donation.