I thought that when a girl became a teenager, she would start having periods to prepare to have children, and after she had around ten periods, they would stop and then she'd be able to get pregnant, and would never have another period again. When my mom told me that women usually have periods for several years, I was horrified.
A childhood belief about periods

others believed things like this
- a male friend of mine used to think that only women who had been pregnant had periods— oiman
- i used to believe that women wore bras because their periods happened in their boobies.Anon
- I also used to think that Mommies didn't have periods. I thought it went away once you had a baby.— T
- i thought the phrase "getting a boner" referred to men getting their periods. — astrid
- When my mom was a child, she thought that while girls had periods, boys had hemorrhoids!Anon
- I used to think that guys had periods, too. — Laurie