Cousin marriage in Appalachia?

Cecil Adams's "Straight Dope" column had a good piece on that popular stereotype:

3. Is inbreeding unusually common in Appalachia? Here's where things get murky. Although the public and many social scientists have long assumed that isolated hill folk often marry their cousins, and some certainly do (ask the Fugates), research on the subject is pretty thin. The most comprehensive look I've found is a 1980 paper ("Night Comes to the Chromosomes [etc]," Central Issues in Anthropology) by Robert Tincher, who at the time was a grad student at the University of Kentucky. Having dug through 140 years' worth of marriage records in a remote four-county region of eastern Kentucky, Tincher argues that (a) yeah, cousin marriage happens in the hill country, but (b) rates vary widely from place to place and even among families in a given district, and (c) it isn't conspicuously more prevalent than in a lot of other places. Point (c) isn't all that persuasive; Tincher's numbers show that as late as 1950 inbreeding was well above what could be accounted for by chance--married couples on average were approximately third cousins. However, the rate had dropped sharply since the peak after the Civil War, when the average couple were somewhere between second cousins and second cousins once removed. What's more, the rate fell quickly after 1950--no doubt due to postwar prosperity, urbanization, and so on--and by 1970 was no higher than you'd likely find in the general population.

According to www.Consang.net, a study of 107 households in Beech Creek, Kentucky in 1942 found that 18.7% were first or second cousin marriages. (Second cousin marriages are a lot less genetic trouble than first cousin marriages, but if one community keeps doing them over and over again, problems can pile up.) In contrast, about half of Iraqis are married to first or second cousins, with first cousins marriages being more popular.

One similarity between old hillbillies with their Hatfield and McCoy feuds and modern Iraqis with their hundreds of militias and insurgent organizations is that cousin marriage generates a lot of clan loyalty, since the same person can play two or more roles (e.g., nephew and son-in-law, or great-nephew and grandson).

The difference is that hillbillies were engaging in cousin marriage mostly because of the difficulties of transportation in the mountains, while in flat Iraq, they are marrying their first cousins because that is socially prestigious.

I imagine the proliferation of the automobile in the hollers after WWII was the key factor in reducing cousin marriage. In the mountains, it's hard to go courting long distances away. A great-grandfather of my wife's was considered a true romantic in his village in the Apennines of Italy because he wooed and won a girl from the town 1,500 feet lower down the mountain, which made for a hard walk back after every date.

Americans are much queasier about cousin marriage than just about any other society. For example, wild man rock-and-roller Jerry Lee Lewis was crucified in the 1950s for marrying his second cousin twice-removed, which is genetically a fairly remote risk for extra birth defects. (There were, however, exacerbating circumstances -- it was the 23-year-old Jerry's third marriage already; his bride was only 13 (and still believed in Santa Claus); and, like Jerry's second marriage, it was bigamous -- he hadn't waited around for either divorce to become final.) In contrast, the impeccably high bourgeois Charles Darwin married his first cousin, a Wedgwood, to the approval of all.

Here's a pro-cousin marriage website.

My published articles are archived at iSteve.com -- Steve Sailer