Sperm washing is a term used to describe the process in which individual sperm are separated from the seminal fluid by spinning it in a centrifuge. The Sperm are then used in intrauterine insemination or in vitro fertilization.

Sperm washing is a standard procedure used in infertility treatment, however, starting in the mid-1990s it was adopted to help HIV discordant couples conceive without passing the virus from the father to the mother or child . The idea is that when the male is HIV positive it will reduce the risk of transmission to the female.

The HIV infection is carried by the seminal fluid rather than the sperm. For years there were lingering doubts about the safety of the procedure, and many couples had to travel to locales that would do the prodecure, such as Italy. Today, hundreds of babies have been born through this process.

Sperm washing was first used in Milan, Italy and has so far resulted in no female becoming HIV positive. The oldest child conceived using this method is now about 11 and is HIV negative. The first known American baby, Baby Ryan was born in 1999 through the Special Program of Assisted Reproduction started by Dr. Ann Kiessling.