Not really my own, but I witnessed it first hand. :-)
I was in the produce section at the grocery store and I overheard this family (Mom, Dad, son - about 10 or 11, and daughter about 6). The mom told the little girl to put something down and when I looked up, the little boy was eyeing the eggplant his sister was holding. He asked his mom what it was and she casually replied "It's an eggplant." The boy got this REALLY confused look on his face and then asked his mom "It makes eggs?!?" I just smirked at the mom (and she at me) when she saw me listening to the conversation.
A childhood belief about general

others believed things like this
- I used to believe that only brown eggs came from chickens. I thought white eggs were made at the store— Destiny
- My daughter once asked if God was short for Godfrey— keefdave
- when asked what i would like to be when i grew up, as a girl of about 5, i answered "a horsey".Anon
- For a while, I thought hand grenades were called "hen grenades" and they were made of rotten eggs.— Athazagoraphobia
- When a "mean girl" in early grade school asked me if I was a virgin I answered "no I am catholic."— Hilary
- My sister once asked her mother why she didn't paint her black....Anon