i used to believe that if you didn't shower or clean your belly button in the shower or bath, a plant would grow from the accumulated dirt in your belly button.
i also thought that babies were born from a woman's belly button and wondered why men didn't have babies because they have belly buttons too.
A childhood belief about belly buttons

others believed things like this
- That the belly button was the place where babies where born from.Anon
- when I was a kid I thought that babies come out of a belly-button.— Ana
- babies come out of your belly button— Kit
- I used to think that if i touched my belly button it would unfold and my belly would be inside out forever. Anon
- I used to think that babies were made when you press your mums belly button.
Then a baby would fall out— Chris Hyndman - I used to believe that babies came out of belly buttons — kels