A childhood belief about general

I used to believe (through some skanty mis-reading of Judy Blume books too young) that menstruation was masturbation, and that masturbation was menstruation. So then, at the proper age, I asked my mother what masturbation meant, and she said, "Honey, you should never be ashamed."

Took me years to make sense of that. And by then I was pregnant!