If it's single-player, I play either depending on the game, but I have noticed I just don't like using female avatars in multiplayer games specifically. Female characters are fine, like in a Left 4 Dead or fighting game-style situation, but I just feel weird playing as a customisable female avatar in online games probably because the few times I tried I got treated like a girl by random dudes which felt so viscerally unpleasant my skeleton almost popped out of my skin and ran for the door