well, not mine. but I remember trying to explain to a friend when we were both about 9 that tescticles were not used to store urine (and thus allow men to pee longer).
A childhood belief about weeing and pooing

others believed things like this
- I remember once a friend of mine told me that when ever you hold in your pee it would make your balls stronger— Zao
- My friend's sister believed the lyrics to Gazza's "Fog on the Tyne" were "Fog on the dinasaurs mine all mine"— Suzanne
- I remember thinking that the "Nude Furniture" store was some sort of naughty place. — Texas Rocky
- A friend of mine seemed to think that 100 pence was worth £6.— Richard Davies
- A friend of mine thought that some olives grew with red edible pits (pimentos).— HA
- I once told a friend of mine that if you held in a smelly burp, it'd turn into a fart. She believed me.Anon