I used to believe that men had absolutely nothing to do with reproduction and that they were actually not needed at all. I thought they only got married and/or lived with women because they would get lonely otherwise and that some of them called themselves "the father" of the woman's children because they liked "pretending" that they helped create them and were as important as the woman.
A childhood belief about reproduction

others believed things like this
- I used to believe that woman had to pay to keep their last name when they got married!!!!!!!— Imaginative_Kidd
I used to believe a man and a woman needed a doctor to put their parts together when they did it.— Phil- I used to believe that the man had to be taller the the woman to married her.Anon
- I thought the line in the song "more than a woman" was "four-legged woman".— boo
- When I was little I used to think that as soon as you were married the woman automatically got pregnant.Anon
- My sister just recently realized that the lyric "more than a woman" wasn't 4 letter woman!— Anne