I used to believe that if you had sex underwater you would give brith to a mermaid.
A childhood belief about reproduction

others believed things like this
- i used to believe that pools had underwater doors that sharks were going to swim out of.— marky
- When I was little I used to think that my mom was a mermaid because she never went swimming with me— Martina
- I used to believe that if I wet my legs in the sea I would become a mermaid.
— andrea - I used to believe that i swam more than 2 hours I would become a mermaid.— M11cazares
- When I was young I used to believe if you died in the water, you'd become a mermaid.— stefanie
- I used to beleive that a mermaid would be singing to you when u listned to a shell. — vprincess