When I was a teenager, I started to think about sex all the time, but nobody ever talked to me about it. I may have been talking with someone of the opposite sex, for instance, whose dress deliberately accentuated their sexual features, and yet both of us would go on idiotically talking about something else, which neither of us was probably really thinking about. Why is there such a prohibition about pointing out the elephant in the room? Why is it considered morally suspect to make one's sexual reaction to someone an explicit feature of a conversation?