In grade school I had a sex-ed class that was taught by a teacher who did double duty as the librarian. She told us that AIDS was contracted from dirty library books. She said the only way to keep from getting AIDS was to make sure you never got a book dirty. (I think this was her passive aggressive way of getting even. We’d just gotten a complete set of ‘Tin Tin’ graphic novels, and they’d been trashed by a kid who’d borrowed them and dropped them in mud). I was a smart kid, and my parents were teachers too. I told them about it and she had to go in front of the school board and justify herself. If I recall, she said something along the line of 'well, we don’t really know HOW people get it, so I wasn’t technically lying, and I didn’t want to talk about how it actually spreads’. This was early enough in the AIDS epidemic that she was only a few years behind the time, but it was information we might have needed. She didn’t get to teach sex-ed any more after that.