I used to believe that getting one's period would be the same as going to the bathroom. When it had to come out, I could just sit on the toilet and it would come out.
Imagine my surprise when I learned the truth.
A childhood belief about periods

others believed things like this
- One day when I was 6 I learned that the toilet was NOT a water cooler. :/— J.C.
- i used to be scared to use the bathroom becuase i believed something lived in the toilet.— robert allen freeman the fourth
- One of my children used to believe that the Pulitzer Prize was spelled Pullet Surprise— Normand
- I thought that toilet paper was bread and by puting it it the toilet i was feeding the ducks at the bottem.— Gringo
- I used to believe that monsters lived in my toilet and they ate my poop and urine when i flushed the toilet.Anon
- I used to believe that if I flushed the toilet before I showered, I would take a shower in dirty toilet water.— Chris D