Cryopreservation of human sperm.

Freezing of human sperm is considered a routine procedure in assisted reproductive technology (ART) laboratories. This article considers various aspects of cryopreservation of human sperm. Human sperm show a specific cryophysical behaviour and different sperm freezing protocols have been developed to avoid damage to the sperm cells. The damage can range from impaired motility and reduced viability to damage to the cellular organelles and effects at the molecular level, resulting in an impaired fertilizing potential. As testicular sperm are immature and only a small number can be retrieved, special techniques are required for successful freezing and thawing of these samples. Banking of human sperm has to be performed in a safe and controlled way and different guidelines are necessary to ensure that this is achieved.