I used to believe that the umbilical cord was attached to the babies groinal area and where it was cut, determined the size of the penis.
A childhood belief about rude bits

others believed things like this
- I used to believe that babies were attached to the umbilicle cord and then stuffed down the throat grow.— anonomous
- I used to believe (about 9) that a penis was a sausage that men stuck in their crutch area to attract women.— Feebs.
- 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.
- I used to belive that however many pieces of cake you had determined how old you were turning!Anon
- I used to think that Frankie Avalon sang, "Hey Penis, Oh, penis..." instead of "Hey Venus."Anon
- I used to believe that gay sex involved a man sticking his penis inside another man's penis.Anon