I like how fable 2 had prostitutes. Plenty of them, yes it was all censored, but that doesn't mean it is not sexual content regardless. It also had them as part of a quest where you hired one for a guy. Similar story perhaps?
Eh.. its pointless classifying a game really. The most immature young ones will think a MA15+ game (or R+ when it finally comes to that) is better than a G rated game just because they are not allowed to technically be playing it. For example, ninja gaiden 2 would be the best thing since sliced bread for them, when to others it depends on what they like. Whereas games like Scribblenauts would be seen as 'childish' and (mind me saying) 'for pussies'.
Really, you can tell you are partially mature when blood, gore, guts, sex and language can be in a good game, not part of one.