I used to believe that when you had your period, urine came out (and not blood). then of course, i learned in sex-ed about the whole thing...it was kind of frightening.
A childhood belief about periods

others believed things like this
- HA! I used to think when you got your period, you would just pee blood...I wish it was like that...if only.Anon
- I used to believe period blood came from the nipples. I thought that was what "padded bras" were for!!Anon
- when I was young, I heard that blood had iron in it. I thought blood was red because it was rusty.— Hunter
- When I was little I thought that my urine was stored in my scrotum until I needed to wee.— Bryan
- I used to believe that guns shot out blood because everytime somebody shot a gun in a movie you saw blood.Anon
- I used to think that tampons were meant to absorb women's urine so they wouldn't have to go to the bathroom.— Koyaanisqatsi