When I was growing up until I learned the facts of life at about age 12 I believed that women had their periods by sweating blood out of their butts. Don't ask!
A childhood belief about periods

others believed things like this
- I thought pads sucked blood from women. It wasn't until later in life that I knew their actual purposeAnon
- I thought that babies came out of our butts until waaaay too late in life o.O— Tina
- i used to believe that women wore bras because their periods happened in their boobies.Anon
- a male friend of mine used to think that only women who had been pregnant had periods— oiman
- when I was young, I heard that blood had iron in it. I thought blood was red because it was rusty.— Hunter
- I believed that all of my blood was stored in the calves of my legs. — Julia