Testicular tissue cryopreservation
This is a more advanced technique aiming at safekeeping male fertility potential. It is the only option for fertility preservation in prepubescent boys that have to undergo spermatotoxic treatment (surgery, chemotherapy etc) before sexual maturity.
Apart from that, testicular tissue cryopreservation may be performed in cases of men with severe azoospermia, where testicular biopsy is indicated. The biopsy material undergoes special treatment in the Andrology lab and usable sperm is extracted, which may be used immediately for fertilization or cryopreserved for future use, especially in the presence of multiple negative predictors of fertility, as every future biopsy is likely to be less successful than the last.