I used to think that Cain and Able were brother and sister (with Able being the girl).
A childhood belief about characters

others believed things like this
- I used to believe my parents were brother and sister, and that everybody's parents were brother and sister.— Rachael
- I used to belive that my mum and dad lived together cause they were brother and sister— Corin
- First I believed that my parents were brother and sister. Then I thought that my dad was also my mums dad. — Rainbow
- i used to think that every family had a brother and sister and they married eachother when they got olderAnon
- My Sister Once Said That Polly Pocket Was A Real Girl That Got Shrunk To Doll Size And Turned Into A Doll.— Jamie
- When I was younger, I saw Madonna's video for "Material Girl". I thought she was singing "I'm a Cheerio Girl"!— Greg