I believed that married people had sex once (obviously) and the number of, er, thrusts, determined the number of children. The woman then had a certain number of conceived eggs inside her just waiting to be born.
Also, the first time I heard the word "rape", I misheard it as "rake". I understood it was something very unpleasant, but being attacked with a rake just seemed a bit obscure.
A childhood belief about sex

others believed things like this
- when i was little i believed that your social security number was the number you were born on the earth — christine
- when i was little i used to think that rape was where you used a rake to attack someone— terrordrone
- When I was a kid I believed that the number 11 was pronounced "onety-one"— Alicia
- I thought everyone only had a set number of breaths before they died.
I breathed slowly for a long time.Anon - i could swear eleventeen was a number for the longest time -- it still sounds pretty convincing.— erin
- I used to believe there was a number "eleventeen". I could never quite work out where it went, though.— Matthew