When I was a very small person, and I'd just got to grips with the fact that eye colour was inherited from your parents, I was convinced that it wasn't possible for two people to have children if they didn't have the same eye colour.
A childhood belief about reproduction

others believed things like this
- i used to think that coloured people had the same colour skeletonAnon
- I used to believe that the sun was an oversized colour changing M&M.Anon
- I used to believe that before colour TV the world was black and white....— Dougie
- I thought that if you wore the colour red, you would go yo hell. — Tone
- I used to believe that the whole world was in black and white before colour TV was invented...— Robsa
- when i was young i always thought that traffic lights were big lolly pops that changed colour— rudiger2