Royal inbreeding
From 1516 to 1700, it has been estimated that over 80% of marriages within the Spanish branch of the Habsburg dynasty were consanguineous.
2013-04-26: Cousin Marriage and Democracy. I had no idea this was so common in some parts of the world.
Approximately 0.2% of all marriages are consanguineous in the United States but in India 26.6% marriages are consanguineous, in Saudi Arabia the figure is 38.4% and in Niger, Pakistan and Sudan a majority of marriages are consanguineous. A recent paper finds that consanguinity is strongly negatively correlated with democracy.
2016-03-07: Middle east Cousin marriage. This explains a lot of problems.
Once common practice in Western societies, estimates suggest the Middle East, along with Africa, continue to have the highest levels in the world. In Egypt, around 40% of the population marry a cousin; the last survey in Jordan, admittedly way back in 1992, found that 32% were married to a first cousin; a further 17.3% were married to more distant relatives. Rates are thought to be even higher in tribal countries such as Iraq and the Gulf states of Saudi Arabia, Yemen and Kuwait.
2018-03-03: US Cousin Marriage
Taken together, the data show a 50-year lag between the advent of increased familial dispersion and the decline of genetic relatedness between couples. During this time, individuals continued to marry relatives despite the increased distance. From these results, we hypothesize that changes in 19th-century transportation were not the primary cause for decreased consanguinity. Rather, our results suggest that shifting cultural factors played a more important role in the recent reduction of genetic relatedness of couples in Western societies.
2022-12-06: The MFP may have been a big part of why Europe developed differently
the Church’s “Marriage and Family Plan” (MFP), which included features like monogamy in addition to an obsession with preventing broadly-defined incest, had important downstream consequences in practically every aspect of life. Young men would be more likely to find marriage partners since a few high-status leaders could not claim a disproportionate share of women, creating incentives for individuals to be more hard-working and less violent. The power of elders was further reduced by an inability to arrange marriages in ways that would keep wealth and resources within the same family, unlike in Muslim societies where the son of one brother would often be wedded to the daughter of another. When incest taboos extended to 6th cousins, an individual may have had 10k relatives that were off limits in the marriage market. This wouldn’t be a big deal in a modern city, but when most people lived in small villages it would have created major difficulties for anyone trying to find a spouse. This led to a population that was more mobile, less embedded in kinship networks, and ultimately more individualistic.
What is sure to be one of the most surprising findings discussed in the book relates to how rare the individual components of the MFP have been throughout history. According to one database looking at 1200 societies before industrialization, only 5% had newlywed couples start their own households, 8% organized domestic life around nuclear families, 15% had only monogamous marriages, 25% had little or no cousin marriage, and 28% had bilateral descent, meaning that lineages are traced through both the mother and father. Christian Europe under the MFP had all five, which wasn’t true for over 99% of other societies. Today, after the rest of the world has been heavily influenced by Western culture, given its success, it’s easy to lose sight of how unique its mating and familial practices have been in the larger historical context.
People prone to individualism would go on to achieve high rates of urbanization and form guilds, universities, marketplaces, and other voluntary institutions that were based on principles of mutual self-interest and competed with one another. Ultimately, Western Europe would conquer the world on the back of the strengths of these institutions, with democracy and capitalism being arguably the most important among them.