What are the roles of the CatSper family of channels in mammalian fertility? How many types of CatSper channels are found in humans? In your discussion be sure to include which channels are expressed on the spermatozoon and the role each channel plays in male fertility. Moreover, discuss how these channels are activated and what Ca2+ does once it enters into the cell. If more than one CatSper channel exists in humans be sure to compare and contrast