When I was a child, I believed boys/men pee-ed out of their belly buttons and I couldn't understand why I had a belly button as well.
A childhood belief about belly buttons

others believed things like this
- i uses to believe that boys wee'd out of their belly buttons.— boys and toilets
- I used to believe that young boys belly buttons would soon change into there willys...Anon
- I used to think that if i touched my belly button it would unfold and my belly would be inside out forever. Anon
- when i was a child i used to think that my belly button was for storing smarties— GemSue
- You couldn't have your belly button covered for too long or it would be harder for you to breathe.— Jess
- I believed that if you pushed your belly button, your bum would fall off.— Wendy