Cryopreservation of human semen is well-established laboratory procedure to maintain the fertilizing potential of spermatozoa during storage in liquid nitrogen. Modern trends in assisted reproduction technologies influenced the indications for human sperm cryopreservation. Spermatozoa are not so sensitive to cryopreservation damage (in comparison with other cell), because of the high fluidity of the membrane and the low water content (about 50%). The effect of cryopreservation on sperm DNA integrity is still unclear. There is no agreement in literature on whether or not affect cryopreservation sperm chromatin integrity.
Male gamete freezing is largely recommended to preserve fertility in those subjects who are exposed to potentially toxic agents, which may interfere with gametogenesis.
Semen preservation before the beginning of therapy should be proposed to all adult men and postpubertal boys. To date, no clinically proven methods are available to preserve fertility in prepubertal males. The testicular cancer survivors have a good chance of fathering a child by using sperm cryopreserved prior to the oncology treatment thanks to assisted reproduction methods.
In the ICSI era, almost all cryopreserved semen sample, even when it contains only few sperm, could be used for subsequent infertility treatment. Genetic damage is unknown.
Cryopreservation is known to cause some changes in sperm morphology, including damage to mitochondria, the acrosome and the sperm tail. The sperm motility is particularly sensitive, and it is generally accepted that it can be reduced to 50% after the cryopreservation/thawing procedure. Due to this fact, it is necessary to choose potential donors with an emphasis on this sperm parameter.