[Tom]

Personally I wouldn't want to sleep with my sister and I think its disgusting but if other people want to, its mutual and they're careful then theres nothing wrong with it really ...

Actually no, I withdraw that. I think its disgusting and people should only be having sex with someone if there are no risks, physical or mental, involved. I know there are risks with normal sex but they're magnified with this; if a child came out of it its likely to be disabled, or it will be, I'm not sure which.