“…Other significant advances in sperm technologies include cryopreservation by vitrification ( 22 , 23 ), refreezing of spermatozoa ( 24 – 27 ), and production of spermatozoa from frozen testicular tissue ( 28 , 29 ). Development in spermatogonia stem cell (SSC) culture opens a new era in the understanding of testis function and male fertility ( 2 , 30 – 32 ).…”