The "sexual" apps that have been on the app store are more stupid novelties for a 13 year old boys. They are the digital equivalent of a Spencer Gifts store at the mall. I mean really, how many "adults" are going to get their kicks adding "jiggle points" to breasts.
That said I don't think it should be banned from the store, just hide it from the front page and take it out of the "top" lists and standard search. Make the "adult" area opt it only.