Claim: The process of spermatogenesis in humans is estimated as taking between 74 and 120 days and is broken into several stages related to particular cells, such as spermatogonium, primary spermatocyte, and two secondary spermatocytes.
Evidence: Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. For humans, the entire process of spermatogenesis is variously estimated as taking 74 days (according to tritium-labelled biopsies) and approximately 120 days (according to DNA clock measurements). The entire process of spermatogenesis can be broken up into several distinct stages, each corresponding to a particular type of cell in humans. spermatogonium (types Ad, Ap and B) primary spermatocyte two secondary spermatocytes