When Did Americans Stop Marrying Cousins? Ask the World’s Largest Family Tree
nytimes.com
nytimes.com
> Two academics, Bilal Barakat and Stuart Gietel-Basten, point out that when women usually have five surviving children, a woman can expect to have 25 male cousins. When the average number of children falls to two, that same woman will have just three male cousins, some or all of whom might be younger than she is, and thus ineligible as marriage partners. The marriage squeeze will be even tighter in cultures that insist, for example, that a woman marry not any old cousin but her father’s brother’s son. Eventually, cousin marriage will be crushed not by medics but by mathematics
https://www.economist.com/news/special-report/21731490-pract...
But....is it actually possible to average much over 2 children for very long? I mean, that's a population boom.
And poor.
Hint my dad had two brothers. One of my dad's brothers fathered six kids. My dad three and his other brother one.
So families sizes of 6:3:1
The majority of my grandmothers grandchildren came from a family with 6 children. Those six have 14 children. My dad and other uncle have two grandchildren total, one each.
>Capital or small capital Roman numerals are widely used in Romance languages to denote centuries, e.g. the French xviiie siècle[26] and the Spanish siglo XVIII mean "18th century". Slavic languages in and adjacent to Russia similarly favour Roman numerals (XVIII век). On the other hand, in Slavic languages in Central Europe, like most Germanic languages, one writes "18." (with a period) before the local word for "century".
One Alison Wolf's main conclusions is that the inventions that actually resulted in women spending less time on domestic tasks were mainly those relating to cooking and food preparation (such as TV dinners and fast food in the 1950's), because the result of a x10 efficiency gain in food preparation isn't that people start eating x10 as many meals, but that the same number of meals get produced with 10% of the time investment.
Here's a famous article about Iraq, where this did not happen:
http://www.theamericanconservative.com/articles/cousin-marri...
Here's a discussion of a recent paper:
http://marginalrevolution.com/marginalrevolution/2018/01/mar...
Finding out that a phenomenon is not due to evolutionary psychology requires careful historical research and that's hard work. Making up evolutionary psychology ideas though takes no time and can make for a great clickbait article.
But cousins are more interesting, because the biological downside of having some ill (or just thick) grandkids must be balanced against the upside of having a tight clan, without divided allegiances, to fight off other clans.
No, they were not the British royal family.
And apparently it was quite an uncomfortable moment.
I relate the story as something which would have been quite normal once, whilst legal now, is fairly taboo. I'm not sure why, although obviously feel and appreciate the taboo.
Taboo because we discovered heredity. Legal because this isn’t prevalent enough to merit national attention.
The real reason we stopped marrying cousins is:
1. We started to live in large cities instead of on farms and ranches. (https://www.census.gov/population/censusdata/table-4.pdf)
2. We could reasonably travel more than 10 miles from home in a day.
In other words, we used to marry cousins because it was too difficult to find better prospects.
Perhaps in the majority groups in the West. Certain communities in the UK still widely practice cousin marriage and suffer hugely in genetic abnormalities. They are not constrained by transport, it is a cultural thing that has not yet been updated.
Why that's true: The reason inbreeding is bad is that the child is at risk of inheriting two copies of a nasty recessive mutation, in a region of their genome where both versions came from the same recent ancestor. However, if the child goes on to successfully reproduce, it's more likely that they had zero copies than two--and in that case the grandchildren have zero copies, which is good for them.
http://www.dailymail.co.uk/news/article-1392217/Muslim-outra...
It's noteworthy that it's simultaneously socially unacceptable to criticize Pakistanis for their preference for first cousin marriages, despite the undeniable harm caused by it, and yet it's also socially unacceptable for whites to have the much less incestuous preference for just marrying other whites, despite the absence of harm:
http://www.slate.com/articles/news_and_politics/politics/201...
> Baroness Flather said because of 'inbreeding', members of the ethnic group are 13 TIMES more likely than the rest of the UK population to have disabled children.
> The Pakistan-born peer has called on the Government to take steps against the issue of unions between close relatives in Muslim communities, which she called an "outdated, un-British custom".
...
> She also accused Britain of a "cowardly reluctance to tackle damaging social practices within certain ethnic minorities".
> In what has been described as a brave attempt to break a taboo she said there was a fear of "accusations of racial prejudice" which has made the issue "unsayable".
> She added: "That is certainly what happened over the disgraceful sex-grooming scandal in Rotherham, in which the civic authorities, including the police and social services, tried to cover up the systematic abuse of more than 1,400 vulnerable girls by predatory gangs of Pakistani heritage men."
http://www.bbc.co.uk/bbcthree/article/6af25e7b-0545-42ba-a6f...
http://www.bbc.com/news/uk-england-leeds-23183102
http://www.independent.co.uk/life-style/health-and-families/...
http://blogs.jpmsonline.com/2015/12/07/cousin-marriages-a-pu...
https://www.ua-magazine.com/first-cousin-marriage-doubles-ri...
Humans unfortunately tend to accumulate negative mutations more easily. Though the upside of lack of predation etc is not something I would want to pass up personally.
No, this is not the reason. Plenty of societies had very strong norms against cousin marriage centuries ago -- from memory below 1 percent in colonial new england?
Others did not. Sometimes because they were just far from the enforcers of such norms. But often for deliberate reasons of keeping family and property together. Saddam Hussein wasn't short of private jets, but was very concerned about losing power, and blood relatives are more reliable. And about 50 percent of his countrymen feel the same way.
Interesting factoid: Freud was married to his first cousin.
It's partly because of misunderstood heredity dangers, but mostly because of increased social pools. (Cousins used to be very socialized with each other, but strangers of opposite sex had minimal opportunities for meaningful interactions.)
It's not just Britain, royal families all over Europe often needed "reseeding" from abroad as need dictated and the family trees got quite intertwined as a result. During the "Great War" of 1914-1918 King George V, Kaiser Wilhelm II and Tsar Nicholas II were all cousins. To be fair, parts of my family tree get a little ahem complicated and resemble bushes.
Nowadays, our royals are branching out and diluting the blood in a very healthy move. Gawd bless em all.
https://www.google.com/search?client=ubuntu&channel=fs&q=fir...
another example of what happens when you have a relatively small population group that marries and reproduces only within their own community, repeatedly for 1000+ years, there's a large number of genetic disorders which disproportionately affect ashkenazi jews:
https://www.google.com/search?client=ubuntu&channel=fs&q=ash...
to the extent that ashkenazi are strongly encouraged by their family doctors to go for special genetic screening, as a routine part of family planning.
Due to cultural sensitivities, the authorities often turn a blind eye on the widely prevalent practice.
https://mobile.nytimes.com/2002/04/04/us/few-risks-seen-to-t...
https://www.sciencedirect.com/science/article/pii/S111086301...
"Conclusion
The present study revealed a higher incidence of certain diseases in consanguineous population with a high significant increase in the prevalence of common adult diseases such as diabetes mellitus, cancer, blood disorders, mental disorders, heart diseases, asthma, gastro-intestinal disorders, hypertension, hearing deficit, G6PD and common eye diseases. This confirms the role of genetic factors across the full spectrum of disease and not only for Mendelian disorders."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666836/
A positive correlation between inbreeding and numerous health outcomes has been reported in several studies. Indeed, unions between relatives are generally associated with an increased risk of abortions, stillbirths (Al-Awadi et al. 1986; Hussain 1998, 1999; Hussain et al. 2001), perinatal mortality (Stoltenberg et al. 1999), and congenital malformations (Abdulrazzaq et al. 1997; Chéhab et al. 2006; Yunis et al. 2006).
Consanguineous marriages are also recognized as being associated with higher risk for autosomal recessive diseases than in the general population (Taillemite et al. 1985; Alwan and Modell 1997; Kumaramanickavel et al. 2002) by favoring the expression of recessive deleterious alleles. Many reports have highlighted a positive association between inbreeding and a number of recessive single gene disorders like achromatopsia (Tchen et al. 1977), Leber's congenital amaurosis, xeroderma pigmentosum (Mokhtar et al. 1998), and metabolic defects like aminoacidopathies and mucopolysaccharidoses (Jaouad et al. 2009). However, some authors believe that a long practice of inbreeding over several generations leads to the elimination of deleterious recessive mutations from the population gene pool (Khoury et al. 1987).
There was also a study looking at the genomes of a large consanguineous pedigree. The amount of pathogenic genome changes seen was shocking, amazing that the phenotypes were normal or mild... that is a gift you will pass on to all your descendants.
However, while the dangers of inbreeding depression are common knowledge, it's worth pointing out that outbreeding depression exists as well. Where lies the ideal balance between these two extremes? Surprisingly, it appears to be marriages between third or fourth cousins, if you use fecundity as a proxy for general offspring health: https://www.sciencedaily.com/releases/2008/02/080207140855.h...
A third or fourth cousin is a person with whom you share first cousin grandparents or great grandparents--essentially a distant relative, or simply put, someone of your own "race," which is quite at odds with the "hybrid vigor" claims often made to tout interracial marriage. Apparently just marrying any old white person (if you're white) gives you all the hybrid vigor your offspring need.
This isn't relevant to generations. My youngest sister is 21 years younger than I am. But we are both part of the same familial generation. My children and her children will also be part of the same familial generation. (This is irrespective of the fact that my sister is a millennial and I am not.)
> The same person could easily show up as someones great grandparent (3) and their great great grandparent (4).
In the case of the graphic, I suggest that they put each person at the highest possible place in the hierarchy and then simply extended the relationship line down in cases like this.
Basically, if you want to understand how people actually behave you need to exclude the living as their relationships are going to be more complex than such neat abstractions suggest. It's only with dead people that you can really understand their life story after-all someone can get married at 25 and again at 95.
Basically, as you start looking at the family tree that actually represents humanity the idea of generation breaks down, do you mean the shortest route from you to someone in ~100,000 BCE or the longest route to some person in ~100,000 BCE. You could say your mother's mother's mother's ... or your father's father's father's but even then the length of the chain going back that far stops being equivalent.
The only thing that becomes meaningful on such a scale is simply generation as unit's of time.
That doesn't make any sense.
The first definition is a parent-child tree relationship. The second definition is a way to characterize the social atmosphere of a given span of twenty-some years. They are structurally different definitions that are not reconcilable.
They can cluster the individuals (green) into hierarchical circles cleanly, then add a line that jumps over one generation, which would not be visible at the resolution of the plot.
They've just done some graph layout to make it look nice.
It wasn’t until after 1875 that partners started to become less and less related.
Mostly people married someone born 10 miles from them. Suddenly steam ships and railroads came.