Incest

Incest is romantic and especiallly sexual goings-on between relatives. It is illegal in most cultures in the multiverse. This does not stop fans, usually of The Movies, writing fanfic involving brothers or sisters having it off willingly, or parents abusing children. The PPC does not condone incest, and it is usually a charge. In cases where a Sue claims to be a sibling of a canon character, and yet still ends up having it off with them, this is still considered incest.