Sperm freezing, or cryopreservation, is the process of preserving sperm cells for later use, which was introduced in the 1950s. It preserves a man’s sperm cells, to maintain fertility if he is facing treatment that risks his future fertility and benefits men at hazard of reduced fertility from several diseases or other health concerns.

There is no known time limit on the viability of cryopreserved sperm, as it seems to be less sensitive to cryopreservation damage than other cell types because of the low water content. Some studies have reported that cellular damage can occur during the freezing and thawing of sperm, but there is no known risk to a baby conceived from donor sperm. Pregnancies have been reported in cases where the sperm was stored for 20 years before thawing and insemination.