I think my sister is a lesbian because i caught her watching girl on girl porn...

She's 8! It's innocent I'm sure...(so what if she terns out to be a lesbian anyway?) Don't worry though, she is a young child she won't be thinking about sex like that. I agree that children shouldn't be exposed to any sort of porn so I would discuss it with your mum if i were you because your little sisters innocence is in danger, and that is something to be preserved for as long as possible. Have you talked to her? If you do, try not to treat her like a weirdo; she's too young to be classed as weared. I'm 14 to by the way.