Until I was probably in kindergarten, I believed that if boys played with dolls or other 'girl toys', then they would become gay, but that if girls played with 'boy toys', they would actually turn into boys. As a girl with friends who were almost all boys, I spent a lot of time playing with trucks and plastic weapons and that sort of thing, and I was positive that I was going to turn into a boy - I would diligently check every morning to see if I had grown a penis yet.
A childhood belief about toys

others believed things like this
- When I was a little girl, I believed that all cats were girls and all dogs were boys. :)— Mary Ellen
- When i was younger i believed that a cat was a girl and dogs were boys.Anon
- when I was a kid, I used to believe that only girls could be my friends and all other boys were my brothers.
— rajat - that cats were only girls and dogs were only boys. I definetly didn't get the whole reproducing thing yet.— Jamie
- I never knew why boys had to lift up the toilet seat...until my friend told me that boys had bad aim.Anon
- I used to believe the Beastie Boys were a boy band. Well, the name sounds similar to Backstreet Boys!Anon