I used to think that once people turned 30, they didn't have sex anymore. 30 was the cutoff date.
A childhood belief about sex

others believed things like this
- I used to believe that people had an expirey date.— Mason
- I used to think that my right hand wasn't my right hand anymore if I turned around.— Mike
- When I was little, I thought that you had to marry someone who was born on the same date as you.— Lauren
- I used to think Billy Idols "Eyes without a face" was "How's about a date" : - )— Shay
- I used to think that there were small people on TV who worked when I turned on the TV— JAVIER
- I used to believe that when people died, they turned brown just like plants do when THEY die.— Joey Schwartzman