Reply #9: Not as many hormones involved in sperm production as there are in egg maturation & release - so not

[iris27]

as many places to monkey with the works. Also, most of the hormones that *are* involved are also linked to libido. Of course our pill can be a libido killer too, but it's only a potential side effect - doesn't strike everyone.

Plus given the many guys who are anti-condom (probably doesn't come close to a majority but enough to have become a bit of a stereotype) some would-be developers might not think there's enough of a market for them to put the time in.