Hard to say. From the female perspective, I am neither put off by sex in a game, nor attracted by it. Nor do I think I would be motivated to buy a game if it tried to appeal to the wild sexual animal inside of me.
Games are not really for sex. There are so so many other `resources` available. Games are like the anti-sex in a way. You are always busy, you cannot be bothered by having a man in your life, it is Saturday night, you are tired, and rather than de-stress the Adam and Eve way, you slash monsters with a sword.
I cannot say if sex sells for men. Part of me wants to believe that most men do not actually want to look at pixellated images of ladies wearning some or no clothing. I do not want to believe that men really wanted to see the origional tomb raider with no clothes or play female characters in games just because you can watch women in scantily clad clothing fight.
Perhaps I am being naive, is this is the case, then I really do not want to know.