For as long as I can remember, I have always known that boys and girls had different parts "down there" however, until I was about 12, I had no idea what the male private parts looked like.
Until I was about 7, I had never heard anyone refer to a males "balls" so I though that men just had a penis, and that was it.
Then once I had heard about men having "balls" I thought that men had a penis, then near the tip of the penis, there was one ball on each side. Then when I was 12, curiosity got the best of me, and I looked it up online and found out just how wrong I had been.
A childhood belief about rude bits

others believed things like this
- I used to think that girls had "balls" and not boys, and the "balls" were slang for breastsAnon
- I used to believe that condoms were weared by girls and boys
both. And they both have penisAnon - 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
- I used to believe that gay guys had sex by sticking their penis in the other's penis.— Fanbrat
- I used to believe that girls pee was in their poop, because they have no penis.— s