Some moron stuck an unwrapped, still rolled condom in my lunch box in middle school. I knew what they were, theoretically, but didn't realize they came lubricated. I concluded that this one, being all slimy, was used. Along with being completely grossed out, I decided that guys must have to roll them back off like pantyhose when they were done. I didn't get straightened out on this until almost my 21st birthday. :)
A childhood belief about condoms

others believed things like this
- I thought you didn't have to go to school when it was your birthday.— M_1
- I used to think my grandmother had two, shall we say, back ends. I didn't realize the second one was cleavage.Anon
- I thought Rock and Roll were 2 musicians, with one who rocked and one who rolled.Anon
- I used to believe that on your birthday, you didn't advance to your next age until you ate your birthday cake.— Casi
- I used to think that your birthday changed every year, and that your parents just decided what day it was.— Daniel
- i used to think that if i didn't celebrate my birthday each year my younger sister would catch up with me— q