Cryopreservation of human semen.

A review is given of the techniques for the cryopreservation of human semen, including the preparation of cryoprotective media, the use of ampoules, straws, and pellets, and freezing and thawing techniques. The use of cryopreserved semen for therapeutic artificial insemination by donor is described. The advantages of cryopreserved semen over fresh donor semen mostly lie in the ability to exclude infections before use and the extra convenience, in spite of the lower success rate and increased cost. The recovery of sperm motility on thawing is described, as are other methods for assessing the degree of damage to the spermatozoa by the freezing procedure. The success rates reported by large semen banks are summarized.