[Current progress in cryopreservation of small numbers of sperm]

Human sperm cryopreservation is an increasingly mature technique in assisted reproduction. However, conventional sperm cryopreservation is not suitable for the cryopreservation of small numbers of sperm. The solution to the cryopreservation of small numbers of sperm may contribute a lot to the clinical treatment of asthenospermia, oligospermia and azoospermatism. Recently, many researchers focus on searching for appropriate carriers for the cryopreservation of small numbers of sperm. This article outlines the effects of current cryopreservation methods including empty zona pellucida, microdrops, other mocrocarriers, testicular tissue cryopreservation and testicular sperm and epididymal sperm refrigeration.