As a child I first heard about Americans going to Mexico and getting "Montezuma's revenge" from drinking the water. And then somewhat later I heard how it doesn't effect the Mexicans who live there. I later learned that that is because the develop a resistence to the germs in the water. But for a long time I thought that Mexicans don't poop and that's why they can't get "Montezuma's revenge" like Americans can from drinking the water there.
A childhood belief about nationalities

others believed things like this
- Because of Pocahontas, I grew up believing Native Americans noises sounded like English to Native Americans.Anon
- I used to believe Mexican food was made from real Mexicans!— Holly W.
- I thought that hydrogen was pure water (since I knew hydro- meant water) and H2O was impure some how— Hexetic
- When I was little I thought that if I stayed a long time in the water I would become a mermaid.— Salma
- I used to believe that if i splashed water on the wall during a bath, the water would turn into spiders— justin
- that bathroom tap water was recycled "potty" water from the toliet. — livingdeadgirl