I was raised in a Christian family, and so I would always be reading stories in Genesis where someone 'lies with their wife' and their wife is 'with child'. So until I finally asked The Question I always thought that pregnancy was this magical thing that happened when women had been sharing a bed with their husband. I thought it travelled through the air.
A childhood belief about getting pregnant

others believed things like this
- When I was little I thought that a honeymoon was when the Husband and wife went to the moon and eat honey.— AmAnDa
- When I was three I used to believe that cow and horse are wife and husband.— xenia
- I always thought that it was "Afully Wedded Wife" Not "lawfully wedded wife"— Sarah
- As a child, I thought that Olivia Newton-John was Elton John's wife and Juice Newton's sister.— Connie
- If a man wore his shirt out, I thought his wife was going to have a baby.Anon
- i used to think that the pope was married but also i thought howcome her wife never appeared on TV— jp