I used to believe that babies came from the mother's belly button. This when I was 17 yet. Got it from "King's Row," a book by Henry Bellaman in which the kid characters talked about where babies came from. And I believed it!
A childhood belief about giving birth

others believed things like this
- babies come out of your belly button— Kit
- When i was between the age of 3-7 i used to bleave that babies came out of your belly buttonAnon
- I used to believe that babies came out of a womans belly button.Anon
- when I was a kid I thought that babies come out of a belly-button.— Ana
- I used to believe that babies came out of your belly button. What else could they possibly be for? — Andrea
- That the belly button was the place where babies where born from.Anon