Dating my third cusion
Such marriages carried no social stigma in the late Republic and early Empire.They cite the example of Cicero attacking Mark Antony not on the grounds of cousin marriage, but instead on grounds of Antony's divorce.By the 1870s, Lewis Henry Morgan (1818–1881) was writing about "the advantages of marriages between unrelated persons" and the necessity of avoiding "the evils of consanguine marriage", avoidance of which would "increase the vigor of the stock".To many, Morgan included, cousin marriage, and more specifically parallel-cousin marriage, was a remnant of a more primitive stage of human social organization. Briggs appointed a commission to study "idiots" in the state, and this study implicated cousin marriage as responsible for idiocy.
Eventually, the nobility became too interrelated to marry easily as the local pool of unrelated prospective spouses became smaller; increasingly, large payments to the church were required for exemptions ("dispensations"), or retrospective legitimizations of children, in what amounted to a 'protection racket' by the church.
In the past, cousin marriage was practiced within indigenous cultures in Australia, North America, South America, and Polynesia.
Various religions have ranged from prohibiting sixth cousins or closer from marrying, to freely allowing first-cousin marriage.
Later studies by George Darwin found results that resemble those estimated today.
His father, Charles Darwin, who did marry his first cousin, had initially speculated that cousin marriage might pose serious risks, but perhaps in response to his son's work, these thoughts were omitted from a later version of the book they published.