Sibling marriage

antocya

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May 2012
5,778
Iraq
I was wondering about the effects of sibling marriage, such as in ancient Egypt among the pharaohs and if it caused genetic problems.
 

Black Dog

Ad Honorem
Mar 2008
9,990
Damned England
It did indeed. Probably the most famous example is Tutankhamen, who was the result of a sister-brother sexual relationship, although the sister in question was not one of his official wives. Scientists have suggested that his early death could have been the result and culmination of several genetic disorders caused by incestuous parents. He certainly didn't have a healthy life, even for a short life.

In fact, even repeated first cousin relationships can cause severe genetic problems, like the most famous case, the Habsburgs. This line of European royals died out due to severe genetic problems caused by repeated inbreeding, most well known is their very long chin and face. Several other royal lines suffered a similar fate, such as the Bourbons.

Our own queen and her husband are fairly closely related.

Contrary to popular opinion, serious genetic effects can show up with even first instances of close incest. I saw one case where a daughter had 4 children to her own father, 3 of those kids had serious defects and one didn't even reach his late teens. The mother was told in no uncertain terms by a specialist why this was.
 

antocya

Ad Honorem
May 2012
5,778
Iraq
You saw one case? Was this an instance of abuse that you saw in your neighborhood or something?

The strange thing about ancient Egypt, they practiced incest over generations but still managed to keep a political system based on this lineage over thousands of years.

I know some royals like the child of the last tsar of the Romanovs had hemophilia and I think that's a genetic disorder which seems to have effected the nobility in some instances.
 

dreamregent

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Feb 2013
4,350
Coastal Florida
Cleft palates were probably also prevalent. Although, statistics will be impossible to determine unless a lot more mummies are put through CT scans. Notably, Thutankhamun suffered from a cleft palate. The male mummy found in KV55, perhaps Tut's father, Akhenaten, also had a cleft palate. Both exhibited some degree of scoliosis and other deformations as well.

As for them maintaining the system with the incest going on, it's important to remember that pharaohs also had numerous wives, any one of which could produce the heir to the throne. So, the child who inherited didn't always have this concern.
 
Last edited:
Oct 2013
357
Pennsylvania
Offspring of siblings have a greater chance of physical abnormalities because these recessive genes will come to the forefront more often than in offspring of nonrelated parents, where they will have less of a chance of being dominant.
 

antocya

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May 2012
5,778
Iraq
That's interesting. I've seen children with cleft palate. My parents helped to host some children from Guatemala with cleft palate while they were in US for surgery. It was difficult for them to use a regular bottle for milk and even after the surgery they had a serious speech impediment. Many children from there also had trouble with a clubbed foot.
 

Black Dog

Ad Honorem
Mar 2008
9,990
Damned England
Antocya: yes, it was a local family I saw. The woman concerned was quite open about her incest with her father, once the kids were born. Her sister also told me that she left home at 15 to get away from such things.

About the Ancient Egyptians- some dynasties went in for symbolic sibling marriage, rather than an actual physical relationship.
 

Moros

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Jun 2012
3,097
Greek mythology has a huge number of incest relationships - fathers and daughters; brothers and sisters; uncles and nieces; cousins - appearing across many generations (and not just among the gods who might be viewed as immune to human diseases). Similar relationships appear in other mythologies, but I don't believe in such profusion.

As far as I recall, mythologies never indicate physical abnormality in the offspring of these unions - in fact they are often shown as heroes and great leaders. Why would this be if the children of siblings/cousins have a higher chance of genetic problems? Did no one notice this in ancient cultures?
 

dreamregent

Ad Honorem
Feb 2013
4,350
Coastal Florida
Greek mythology has a huge number of incest relationships - fathers and daughters; brothers and sisters; uncles and nieces; cousins - appearing across many generations (and not just among the gods who might be viewed as immune to human diseases). Similar relationships appear in other mythologies, but I don't believe in such profusion.

As far as I recall, mythologies never indicate physical abnormality in the offspring of these unions - in fact they are often shown as heroes and great leaders. Why would this be if the children of siblings/cousins have a higher chance of genetic problems? Did no one notice this in ancient cultures?
At some point, they almost certainly made the connection between incest and birth defects. The tendency toward keeping it in the family among royals notwithstanding, I think we get an indication of that from ancient codes of behavior specifying prohibitions against sexual relations between close family members. Examples would include the Hebrew Bible and the Code of the Nesilim.
 
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History Chick

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Jun 2010
3,336
Colorado Springs (PA at heart)
I know some royals like the child of the last tsar of the Romanovs had hemophilia and I think that's a genetic disorder which seems to have effected the nobility in some instances.
I don't believe this has anything to do with inbreeding. The original carrier of the hemophilia is believed to be Queen Victoria and many of her daughters and granddaughters, also carriers, married into royal and noble families throughout Europe so the defect was passed on this way. Hemophilia only needs one carrier to manifest in men - the issue with inbreeding is that the gene pool from both parents gets smaller and smaller. Alexei Romanov had hemophilia because his mother was a carrier and passed it onto him, not because his parents were second cousins, which is generally considered not closely related enough to significantly increase the risk of birth defeats.

The only way inbreeding would influence hemophilia is if it were to manifest in a female - because females have two X chromosomes and the hemophilia is an X chromosome disorder, she would need to inherit two defective X chromosomes, one from each parent. So if her father had hemophilia and her mother was a carrier, the female child might have hemophilia as well - and this is more likely to be the case if both parents have it because they share a common, near ancestor who was the carrier for both of them. Since I don't know of any case of royal or noble females in Europe having hemophilia, I think it's safe to say the hemophilia which occurred in several European royal families had nothing to do with cousin marriages.