Dude I read this book once (Yes ONCE).
About a family in Nova Scotia same thing except there where clans of them all around. I think it was Just outside of acadia or wherever the big Universty is. Really creppy shit though. It was the same time that X-files episode was on too. So I had this horrible vison in my head while reading it. The book was written by one of the female family members who 'escaped' although her Mom was also her aunt or some crazy shit.
"I married a widow who had a grown up daughter. My father visited us often, fell in love with my step-daughter and married her. Thus he became my son-in-law, and my step daughter became my mother, because she was my fathers wife.
Soon after this my wife gave birth to a son, which of course was my father's son-in law and my uncle for he was the brother of my mother.
My father's wife also became the mother of a son. He was of course my brother and also my grandchild, for he was the son of my step-daughter.
Accordingly , my wife was my grandmother, because she was my mother's mother. I was my wife's husband and grandchild at once, and as the husband of a person's grandmother is his grandfather...