About sex.
When I was at intermediate age, I thought the penis and vagina when I had puberty classes back in the day were a puzzle. Connecting one piece to another. When I grew up at college I knew that sex was a thing that parents do when they get married. I now know that God has made sex a beautiful thing between a husband and wife.
A childhood belief about sex

others believed things like this
- When I was little I thought that a honeymoon was when the Husband and wife went to the moon and eat honey.— AmAnDa
- When I was three I used to believe that cow and horse are wife and husband.— xenia
- I used to believe that an erection only occured after a male was married and that it was a permanent thing.Anon
- i used to think that the pope was married but also i thought howcome her wife never appeared on TV— jp
- i used to believe that everyone got married the day they graduated from collegeAnon
- I used to believe that you got married right after you finished high school or college. Anon