I used to think that all boys had boy hair, and all girls had girl hair.
When my sister was little (though she is only two years younger than me), her hair looked boyish, so I thought at first that she was a boy. I was in for a big surprise when my dad told me that she was a girl.
A childhood belief about hair

others believed things like this
- I used to think that everybody's hair was black and if you had blond hair, you dyed your hair.— ~_~CoolKid93_~_
- I thought Buckwheat from "The Little Rascals" (1994) was a girl because he had long hair!— Molly
- When I was little I thought that dying your hair means you kill your hair.Anon
- I used to hold my hand over my hair whenever i left the house and it was windy incase my hair blew away— lisa
- I used to believe that you could curl your hair by twirling a strand of hair wrapped around your finger— Anonymous
- I believed that if you ate a piece of your own hair, a new strand of hair would grow on your head.— Ryo