Excuse me while I throw up.
Actually I read about an Iceland study which said that relationships between more closely related couples (third cousin or so) tended to be more fruitful than relationships between complete strangers. I do agree though that first cousin is genetically risky but it appears to work out in their case.
Want to hear something vaguely throw up worthy consider Lazarus Long who was married to his twin female clones, and his rejuvenated mother. I like Heinlein and all but that was just a bit out there for me.
Everyone is related, apparently.
11 children? Geez, half that number and I would blow my brains out.