I used to believe that Big Macs were a strictly "male" food, and if a woman were to eat one, then the first time, she'd turn into a gigantic, obese, cursing "butch lady" with a cigarette permanently attached to her lips (like the Phone Sex lady on Beavis and Butt-Head, lol), and the second time she ate a Big Mac, she'd turn into a man altogether. Also, I believed that it was against the law for children to eat the "adult" meals at McDonald's, and vice versa--except for teenagers, who were so "old" that they were practically grown-ups anyway, at least in my young mind. ;)
A childhood belief about dangerous food

others believed things like this
- I used to think that Chris de burgh song Lady in red was Lady in Bread
— Omega-R-Fox - My Brother used to think that Chris de Burgh was singing 'Lady in bed' instead of lady in red'— Kerry, Manchester
- I used to think the song "dude looks like a lady" by aerosmith was "doodles like a lady"— I used to believe
- I used to believe the song "Dude Looks Like A Lady" said "Do It Like A Lady"— jvf
- when i was little thought that ants changed traffic lights from green to red and vice versa.Anon
- When you lie your lips move or your eye turn green— Tanya