When I was in second grade, I heard people talking on the school bus about sex and getting pregnant. I came home and asked my mom (a very religious woman) about it. She explained that sex was something you do after you're married and that's how women get pregnant; the man and the woman both get naked and kiss and the sperm from the man's "extra part" fertilized the egg that came from the woman's tummy.
I had no idea what the "extra part" was (my parents were divorced and I had a sister, so I had never seen a penis), but I deduced from this that kissing when naked caused a sperm and egg to join in midair between the couple, and then go back into the woman's tummy and make a baby. I thought that you must be completely naked for this to work, so just tying a rope around your waist or something would prevent pregnancy.
A childhood belief about getting pregnant

others believed things like this
- I used to believe once a man and a woman lay naked caressing each other, the woman would be pregant— oiman
- I use to believe that the man peed in the woman to get her pregnant. Didn't know about sperm until sex ed. — das
- I used to believe that a baby's sex was determined by whether the sperm had a picture of a man or woman on it.— David E.
- When I was little I used to think that as soon as you were married the woman automatically got pregnant.Anon
- That to make a baby a man (over 21 & under 25) had to kiss a woman (over 19 & under 21).— Johny
- When I was younger I thought that when a woman was pregnant she would feed her baby through her belly button!— Hennie