Man-made versus female-made environment - will the real capacitation please stand up?

Two recent reviews discuss the importance of the female tract in regulating the function of the spermatozoon during its eventful journey to the site of fertilization in this journal. However, our understanding of the nature of this journey, specifically in the human, is remarkably poor. What is also clear is the discourse between what is likely happening in vivo and the design of our experiments in vitro. Our conclusion is that, to date, we have been studying the spermatozoa in the wrong environment, in the wrong way and at the wrong time.