Evidence supporting the existence of sperm maturation in the human epididymis

Abstract
Zona-free hamster oocytes were used to evaluate the penetrating capacity of spermatozoa recovered from the caput, corpus and cauda segments of 5 human epididymides. Spermatozoa ability to bind tightly to oocytes increased in spermatozoa from successive segments. Only spermatozoa recovered from the cauda epididymidis were able to penetrate the oocytes (26%). Apparently in man, a gradual process of sperm maturation occurs in the epididymis, as has been observed in numerous other species of mammals.