Although I knew about fucking in theory at least, I still believed the baby came out of the woman's belly button until I was 11 or 12.
Much later, when I was a schoolteacher, we were having a discussion in the staffroom about abortion in rape cases. It turned out that this 30-year old, married teacher believed a woman could only get pregnant if she had an orgasm.
A childhood belief about getting pregnant

others believed things like this
- I used to believe that when a woman was pregnant, she fed the baby with a tiny spoon through her belly button.— Marie
- When I was younger I thought that when a woman was pregnant she would feed her baby through her belly button!— Hennie
- I used to believe that a woman gave birth by pressing her belly button and the baby popped out.
— Tasha K - When I was little I used to think that as soon as you were married the woman automatically got pregnant.Anon
- I used to believe that when a woman was pregnant the baby could play monkey bars on her ribs.— Laura
- I used to think that if a black woman or man and a white woman or man had a baby, it would be Asian.Anon