Misconceptions about sex

Dan Savage writes in his weekly column about the misconceptions adults remember they had when they were kids about sex. It's at times amusing, at times gross, and at times horrifying. What were your misconceptions? I don't recall any as when I was about 7 or 8 I went and rented a book from the school library. The librarian wouldn't let me check the book out because I was not old enough. She called my mother to tell of the transgression, but my mother chewed her out telling the librarian that she was certain that there was no book in the grade school library that would be too forward for her children. Perhaps my mother was just happy to be avoiding the topic, but it was a rather cool thing to do.