About orc-women, they obviously have to exist, unless the orc race can somehow reproduce...by themselves...
Either way, I do not like to go into the biology of the stuff. I think that orcs were created in mockery of men and elves in the first place, and I would then also think that females as well as men would be represented in the orcs' race.
Just another question to ponder: Where would the females dwell? Barad Dur is not exactly an orcs' idea of a honeymoon...