[noparlpf]

Originally Posted by Jeff the Green

Tangent:

Spoiler

Because some inbreeding is good. While sibling relationships have a greatly increased risk of genetic disease, cousin relationships don't have a significantly increased risk (for most populations) and have fewer fertility issues. The closer a woman is related to her partner, the less likely her body will attack the sperm on its way to the ovum.

Ah, that makes sense. Okay.