I was in fifth grade when I first heard of the human reproduction process: a friend ran into the classroom right after recess and yelled, "Hey! I know how babies are made! The man sticks his dick in the woman's --" and right then someone made a noise and I didn't hear what the last word was. For a long time I thought of where one might put the thing to make a baby but really couldn't think of a good answer. Still looking.
A childhood belief about reproduction

others believed things like this
- I used to believe that oral sex was when you yelled, or made noise while having sex.— M
- My friend used to believe baby oil was made from babiesAnon
- I used to think that the word blurb was a noise that people made when being sick. Bluuuggghhh.— Natasha
- I thought baby oli was made from pressed babies.Anon
- In first grade, I thought that if I've never heard of a word before, then it wasn't a word.— Destiny
- I used to think that babies were made when you press your mums belly button.
Then a baby would fall out— Chris Hyndman