Guide to dating your cousin
With the rise in the West of the Roman Catholic Church marriages between cousins were officially more constrained.Adam Bellow argues in In Praise of Nepotism: A Natural History that there’s a material explanation for this: the Roman church used its power over the sacrament of marriage to control the aristocracy.The same dynamics do not necessarily apply outside of the developed world.A friend whose father is Arab once explained that cousin marriage was so pervasive in that culture in part because you marry who you meet, and it is difficult in Arab societies for men to meet women who were their cousins.More precisely the coefficient of kinship between two first cousins is 1/8.
Marriage between cousins were presumably more common.
If I told you than the chance of first cousins having children with a birth defect is 4-7%, vs.
3-4% for a non-consanguineous couple, it might not sound that bad.
If the allele is “good,” that is, totally normal/wild type, not associated with any pathology, then we’re in the clear.
That’s why most first cousin marriages don’t produce children who are monsters.
With a more fluid and harshly meritocratic global elite the attraction of cousin marriage seems to have diminished in the Western world. He is an American citizen born in Australia married to a Cantonese woman with grandchildren who are 1/4 Ghanaian, 1/4 Dutch, 1/4 ethnic Scotch (Australian) & 1/4 ethnic Estonian (Australian) .