This is an old revision of this page, as edited by Slrubenstein (talk | contribs) at 09:22, 31 May 2002 (explanation for change). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 09:22, 31 May 2002 by Slrubenstein (talk | contribs) (explanation for change)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Some biologist should add some numerical information about likelihood of birth defects after incest, say between brother and sister. Also some general information about why mixing is good would be useful. --AxelBoldt
At the level of brother and sister the probability of birth defects goes up noticeably, but not enormously if the gene pool is fairly healthy. Maybe it almost doubles. Some of the more common birth defects (hare lip etc) are probably not due to genetic causes. For first cousins, the increase is down in the noise. Inbreeding can have advantages (ask any plant or animal breeder), but breeding individuals who are not closely related also has advantages (again ask any plant or animal breeder). The best way to get a healthy population seems to involve a mixture of both.
As to why, that is a very complicated thing that is not quite fully understood yet. It would take a very knowlegeble geneticist writing a very long article to explain even what we now know.
I am not sure how this relates to incest for humans. A lot of people would not want to think about humans in these kind of terms, of deliberately breeding to improve the species. Also incest is not quite the same as inbreeding, since in most juristicions it includes various relationships without close blood relationship, and it also includes sexual relationships that do not produce children.
True, but that's just a result of confusion by priests and jurists. It's clear that the incest taboo is there because of genetic reasons.
In Germany for instance, it is legal for a sister to have oral sex with her brother, but penetration is illegal. That makes eminent sense. But the article should explain why.
Bullshit. There is no such thing as an "incest taboo" except in modern societies. It certainly didn't arise due to genetic reasons or evolution.
Is it really clear that the taboo is for genetic reasons? The fact that most traditional versions of it are not very precise in preventing genetic trouble, should be a hint that other reasons should be considered. The genetic reasoning may well be a modern rationalisation for an old custom. It is unlikely that the ancients in the cultures where the taboo existed did the detailed and careful statistical analysis needed to show that inbreeding can increase short term genetic risk. They certainly did not have the theory needed to understand why.
For the definition of incest found in some tribes, that no sex inside the clan is allowed, there is a much more obvious explanation. It is to improve the unity of the tribe by forcing the clans to remain friendly. For other versions of the taboo it is hard for me to imagine any rational reason based on evidence available to the people who first invented it.
- i haven't read anything on this in a while, but my impression is that property had lots to do with it. For example, I seem to remember that in Classical Athens, an uncle could marry a neice if she were the sole heir to her father, in order to keep the property in the family. On the otherhand, I'm pretty sure that Post-Christian Rome had a 7 degree limit, which was also held as the standard for the Franks, although they tended to look at the degrees slightly differently. Of course, this doesn't work if you look at the marriage of Louis the Pious and his son to two Welf sisters, so that Charles the Bald's maternal aunt was also his sister-in-law... Off to hunt in Herlihy and Wemple -- I think that's where I read this stuff...JHK
I restored JHK's recent contribution, and also revised the article. "incest" is a term that has many meanings and uses, and one meaning and use is to describe prohibited marriages. I agree that it is sometimes important to distinguish between prohibited sex and prohibited marriage, and I revised the article to make this clear -- I provided two different definitions of incest, and an specific case that includes an example of a forbidden sexual relationship and a forbidden marriage. I also removed some tendentious polemic. SR