Wednesday, April 13, 2005

The Sociology of Incest

Professor Henslin of The Ohio State University (why don't they just call it Ohio State University instead of The Ohio State University) has posted a very interesting article about the sociology of sexuality. It's in a pdf file, though, so you'll need Adobe Acrobat Reader to read it.

He makes the excellent and very simple point that there are some sexual activites that societies don't much bother trying to prohibit, while there are others that they invest a lot of effort into preventing. Rape is the most obviously prohibited thing. But incest isn't much farther down the list.

Naturally, what is prohibited varies a great deal from society to society and--even more interesting--within a society over time. Did you know that it wasn't till 1908 that England passed its first laws outlawing incest? And did you know that child pornography wasn't made illegal at the Federal level in the USA until the 1970's? Clearly, some prohibitions that we are used to (whether we like them or not) weren't always in place. Mores change, and our laws evolve with them.

Dr. Henslin's article gives a good quick overview of the thinking on why most societies have some form of incest taboo. Less ink is devoted to why it might differ over time within a society or between societies, however. But I think that generally reflects the poor state of academic research into incest. Thanks to the anthropologists, we know what different societies' mores are with regard to incest, but not much about how often they are broken or how they evolve. The article is a good overview, however.

Saturday, April 02, 2005

Genetic Sexual Attraction and Incest Avoidance

Most people find incest gross. But if you ask them about incest in general, they will be less grossed out than if you ask them having sex with one of their own relatives. This fact gets to the heart of incest avoidance--the tendency of animals (including people) from the same family to avoid sexual contact with each other.

There are many theories to explain this well documented behavior. Some are sociological. Some are biological. But no matter what theory you may have as to why incest avoidance may have proven beneficial (fewer birth defects, or lots of advantageous, alliance building marriages to members of other families and clans), you still need an actual mechanism that explains exactly what makes individuals from the same family avoid each other later as sexual partners.

One line of thinking has to do with the ability of mammals to smell each other. In particular, there is evidence that we can subconsciously smell each other's histocompatibility antigens. These antigens are chemical tags onto which invading pathogens (bacteria, viruses) can attack your cells.

A good evolutionary strategy is to have kids with someone whose antigens are different from your own. That way, you'll be spreading your children's risk with respect to germs. By giving them lots of different antigens (which you will do if you mate with someone whose antigens are very different from your own), you'll be making it harder for any one virus to come in and easily take over all your kid's cells. By contrast, if you mate with a near relative, your kid will have a very limited set of antigens.

So one line of thinking about incest avoidance is that we avoid our relatives because they smell like we do--that is they have antigens that are so similar to our own that we know they are kin because they smell like us. This explanation has significant attractiveness because it is known that animals (including female humans) do in fact prefer mates with histocompatibility antigens very different from their own.

Another line of thinking is that the actual mechanism for incest avoidance is simple contact. In particular, you don't want to fuck as an adult anyone you were in contact with as a child. For instance, if you were raised by your biological parents, then you'll avoid them later on for partners. But it also goes for step parents and adoptive parents. Whoever you were around--be they actual blood relatives or not--you'll want to avoid. Good evidence for this comes from the fact that children raised together en masses in group homes for children on Israeli Kibbutzes almost never married anyone who lived with them in the same dormitories growing up. It didn't matter whether they were siblings or not. What seemed to matter was simple proximity growing up.

A very interesting paper in the proceedings of the Royal Society (London) presents evidence in favor of the raised-together mechanism for incest avoidance, and thus against the antigens mechanism. The three authors find that the longer kids were raised together, the more grossed out they are later on by the thought of sex with each other. Of particular importance, this is true no matter whether the kids were in fact related to each other. That is, there is not so much incest avoidance as there is avoidance of having sex with anyone you grew up with (and by grew up with, I mean lived with in the same residence.)

This research is also very interesting in light of a phenomenon that has come to be called genetic sexual attraction (GSA). This term refers to the fact that siblings and parents separated by adoptions many years before often find themselves hugely sexually attracted to their relatives later on if there is a reunion (as between a young man and his biological mother whom he hasn't seen in 25 years because she gave him up for adoption when he was an infant.)

This appears to be a big problem and most of the big adoption websites now have a page or two devoted to warning people about it before they go through with a reunion. Here's an article from the London Guardian about GSA. And here and here are some links to adoptions websites' warnings/suggestions. What is fascinating here is that GSA seems to be totally consistent with the idea that unless you grow up with someone, you are not going to avoid them later on as a sexual partner. In fact, what seems to go on with GSA is that when reunited, people find that they have huge amount in common and lots of shared interests and look alike, etc etc. All things that are attractive. And given that they have no tendency to avoid each other (since they didn't grow up around each other), sex is an natural outcome. Also check out the very candid site run by Barbara Gonyo, another who experienced GSA.

Friday, April 01, 2005

State By State Incest Statutes for the Entire USA

Here is a link to a pdf file compiled by the National District Attorneys' Association of each and every one of the 50 States' statutes regarding incest. I have not read through it in detail, but the major incest board poster Hans has read through it all (bless him) and has concluded (after warning that he's no lawyer) that the laws seem to indicate that "consensual adult incest in general is legal in Michigan, New Jersey, and Rhode Island. And consensual adult incest, with the exception of incest between parents and children, is legal in: Ohio."

If this is in fact the case, I'm pretty well shocked. I had assumed that incest was strictly prohibited under law everywhere in the USA. It would be interesting to see if there are other jurisdictions around the world where it is not illegal.

UPDATE: It turns out that the National District Attorneys' Association condensed the above long winded listings of each state's incest statutes into this handy table. With the table to cut through the clutter, it seems that Hans was very right about Ohio and Rhode Island, but not about Michigan and New Jersey. Kudos to Kia for finding the original link.

Birth Defects and Legal Prohibitions on Incest

Over the last 40 or so years, American courts have increasingly ruled in favor of a very broad interpretation of individual sexual rights. Or, stated somewhat differently, the courts seem to see less and less justification for the government to intervene in citizen's sexual matters on the grounds that their behavior may have consequences for other people not directly and immediately involved in the sexual act itself.

This is probably due to the fact that any particular sex act has, truly, grown less consequential. For instance, modern antibiotics have basically eliminated sexually transmitted diseases as any sort of major public health problem. Compare that to the mass absenteeism and morbidity that used to be caused by STDs, and which was the common lot of anyone not strictly in a monogamous sexual relationship before the advent of these wonder drugs. Similarly, modern birth control methods now mean that sex is detached in a way never before possible from procreation. While sex in general matters, individual sex acts--and thus acts of sex among individuals--are simply much less weighty than they used to be.

This means that pretty soon, there will be a battle fought out in either the legislatures or the courts (more likely the courts) about whether or not society really has any interests in prohibiting consentual adult incest. The major argument right now is that it might lead to birth defects. But in a society that allows for abortions even up to the moment of conception (partial birth abortion, anyone?), and in which you can screen for most developmental anomalies in utero, this is something of a red herring. But even more of this justification for prohibiting incest would be removed if it were found out that incestuous couplings just didn't really cause all that many birth defects.

Along those lines, please check out this very nice article by law professor Joanna Grossman on the legal implications of a new study that shows that cousin couples have rates of birth defects among their children that are not much different from those of non-related couples. If this research holds up, there will be very little for opponents of cousin incest to stand on legally.