I was the oldest of four, and my brother came after me. By the time my little sister came along, we had noticed things like the differences between boys and girls. We were convinced that we had been born as girls, and that our penises had "popped out" as we grew older. Our poor sister waited patiently for almost two years for her's to materialize. I think she's caught on by now.
A childhood belief about rude bits

others believed things like this
- I used to believe both boys and girls had penises so i thought sex was when they tied them together.Anon
- My oldest sister is 15 years my senior. I used to think that she was older than my mom.— Callie
- I used to believe that little boys grew up to be girls and little girls grew up to be boys. — Darin
- i used to think boys were born from men and girls were born from women— swag lad123
- My older sister had me convinced that noodles grew on trees, but that rice was man-made...— Trusting little brother
- I thought that the difference between girls and boys was that girls have teeth.
Anon