Because boys go #1 standing up while girls sit down, this must mean that boys don't ever have to go #2 since you have to sit down to do it. This mis-belief was cleared up when I walked in on my dad doing #2 after he had neglected to lock the bathroom door.
A childhood belief about weeing and pooing

others believed things like this
- I thought that the difference between girls and boys was that girls have teeth.
Anon - I never knew why boys had to lift up the toilet seat...until my friend told me that boys had bad aim.Anon
- I used to believe the Beastie Boys were a boy band. Well, the name sounds similar to Backstreet Boys!Anon
- I used to believe that little boys grew up to be girls and little girls grew up to be boys. — Darin
- when I was a kid, I used to believe that only girls could be my friends and all other boys were my brothers.
— rajat - I used to believe that tigers were girls and lions were boys— Ruth