I remember when I was 6, I used to believe that boys had vaginas too. I didn't know what a penis was.
This one time, my family went to the beach, and we had to stop halfway there so my brother could go to the bathroom, but he had to go bad and wouldnt make it to the the nearest restroom in time, so he had to go in the woods.
I decided I had to go too, so my mom said to go in a bush. I didn't want to go to the bathroom alone, so I went next to my brother.
I saw his penis and totally freaked out. I said, "Theres an alien on you!"
He freaked out too and was like, "Where? Where?"
And I said, "There!" Pointing to his penis.
He takes one look and says, "What are you talking about? This is pee pee."
And I'm like, "YOU'RE FRIENDS WITH IT?????!!!!!!"
I told mom he was hiding an alien in his pants and they laughed at me the whole way to the the beach!!!!
A childhood belief about reproduction

others believed things like this
- I used to think that boys didn't get their penis until they were 18 which was legal adulthood! — beckles
- 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 every time you had sex your penis would get ywice as big.Anon
- I used to believe that a boy's penis came out of his bellybutton, so you couldn't see it all the time.Anon