"The supposed depravity of cousin marriage: a moral panic we'd be better off without"

Amen to that. This is so on point:

It amazes me that so few liberal-minded Americans know this, but in fact anxiety over cousin marriage is a peculiarly American thing, the product of the same nineteenth-century anxieties about supposed backwoods degenerates and “corruption of our racial stock” that led to the early-twentieth-century boom in “eugenics.” First-cousin marriage is illegal in thirty states, and an outright criminal offense in five. By contrast, first-cousin marriage is legal in all of Europe save for Romania, Bulgaria, and Croatia, and legal as well in Australia, New Zealand, Japan, Canada, and most of Latin America.

[...] There are genetic risks in first-cousin marriage, but they’re fairly marginal, and can mostly be addressed by getting genetic counseling before having children. For marriages of second cousins and the like, the risks are nearly imperceptible. In fact, if the consequences of first-cousin marriage were as calamitous as many Americans seem to think, the human race would have died out tens of thousands of years ago. For most of history, most humans have lived in small communities and not traveled very far from home; cousin marriage has been extraordinarily common, and yet has somehow failed to yield a planet full of shambling six-fingered freaks.

The problem with finding it hilarious that some states ban same-sex marriage but allow cousin marriage is that you’re basically trashing those states for having laws which are progressive. And when you slam a state like North Carolina with this stuff, you’re participating in a long American history of using cousin marriage as a way of imputing that poor rural people, particularly poor rural people in Appalachia and the South, are depraved, terrifying, and other. Their physical infirmities aren’t products of poverty, malnutrition, and abuse; they’re because something’s fundamentally wrong with them as organisms. It’s not a rhetorical tradition to be proud of.

The comments are gold:

• A further irony of the "ha ha North Carolina bans gay marriage but lets cousins marry" wheeze: In fact North Carolina restricts cousin marriage slightly more than, for instance, New York State, where all forms of cousin marriage are completely legal. Indeed, the actual list of states that allow unrestricted cousin marriage includes quite a few other states that are neither Southern nor significantly associated with Appalachia, including California, Colorado, Hawaii, New Jersey, Connecticut, Rhode Island, Massachusetts, and Vermont.

• It's perfectly legal and socially acceptable in Britain, though rare other than among recent Asian immigrants [...] The idea that it is considered harmful in America would strike most of us as weird. [...] On the other hand there has been some xenophobic political grandstanding about it in recent years, particularly in parts of the north of England.

• I always suspected anti-cousin-marriage rhetoric had all the hallmarks of the eugenics movement. The first time this was really brought home for me was in an online discussion around Harry Potter fanfic, in which some British fans said they were sick of Malfoy incest-fic being justified by "they're aristos, so they marry their cousins, and it's only a tiny step from that to sleeping with siblings/parents." Somebody asked "wait - Americans think cousin marriage is incest?" An American asked - "Wait - non-Americans *don't*?"

  The really horrifying thing, when I investigated further, were the anecdotes about present-day people who were told by their doctors "Well, you seem to have turned out healthy despite your parents having been cousins, but no doubt *your* children will be freaks even if you marry a non-cousin, so you'd better have yourself sterilized." [Of course that's not how it works at all. Regardless of your parents, your own kids will be fine if you don't reproduce with a close relative. Anybody who claims that they have some problem because their own grandparents were cousins, has no idea what they're talking about.]

• In 19th century Britain (and its possessions, and to a lesser extent the US) the hot issue for a while was marriage with a deceased wife's sister. It was the subject of numerous Parliamentary and internal church debates, as well of popular moral panic in some quarters. And it's almost completely forgotten now.

• I believe that was a holdover from medieval Church rules about consanguinity, with the logic that "sister-in-law is sort of equivalent to sister, so no marrying them." (I think this actually goes back to Leviticus.)

• What's on my list of History To Learn is how the Christian West's extensive taboos against consanguinity in the Middle Ages gave way to preferment of cousin marriage in the Reformation and beyond. In the mid-twelfth century, Eleanor of Aquitaine and Louis VII of France's marriage was annulled technically because they were "related within the fourth degree." This wasn't the real political reason, and Eleanor's next husband, Henry of Anjou, was a closer relation: but the point is that being fourth cousins once removed was grounds for declaring a marriage illegitimate. Contrast this with Victoria and Albert in the the 19th century, who were first cousins and of a family that had long had a habit of marrying inside the gene pool. What gave?

• Back in the Hellenistic era, the Ptolemaic dynasty consolidated its hold on Egypt by a number of means. One of the more dramatic ones was the theft of Alexander the Great's body, but slightly better-known is reintroducing the native Egyptian custom of sibling marriage in the royal family.

  Many Greeks, even those in the royal court, found this somewhere between disgusting and outright barbaric, and I use the word deliberately. They considered it extremely offensive that a Hellen(ist)ic royal family should go native to that degree. The Romans were also pretty squicked by it, possibly picking it up from the Greeks.

• One of the secrets of Egyptian inheritance was that it was in the female line: the husband of the queen ruled, then the husband of the queen's first daughter ruled. This goes a long way to explaining why Ramesses II, after his sister-wife's death, married his daughter, and on her death, married another daughter, and on her death, married a third daughter.

• Come to think of it rules and laws and taboos only make sense if they ban things that some people do but most people don't. You don't need laws against cutting your own feet off or eating your own excrement because so few people want to do it there is no need for them. And there is no point in making a rule against something that nearly everyone does because they will carry on doing it anyway - and probably change the rules. The very existence of incest taboos in effectively all human societies is probably evidence that most people don't do it but enough people do to worry the rest of us.

• Famously, Darwin's family was absolutely full of married first cousins (and Charles Darwin was married to his first cousin), and yet seemed to manage to contribute a thing or two to the world. and live relatively good lives.

  At any rate, there are genetic reasons why some people ought not to have kids, either singly or as couples. Not marrying your near relatives is a heruistic for avoiding some of those problems, but you can probably do rather better with modern technology. I know a lot of Jewish couples get genetic counseling to avoid Tay Sachs and a bunch of other related diseases; I assume over time that will become more and more common. Getting married and having kids is surely worth spending a thousand bucks on some tests and an expert to interpret them to head off potential problems.

• There was a case in Michigan in the 1970s where a married couple discovered that they were full genetic siblings. They'd been given up for adoption and raised apart and unaware of each other's existence. They argued unsuccessfully that they had no sense of each other as brother and sister, and no common family history, and should be allowed to remain married.

  The judge in the case invalidated their marriage, and forbade them from living together as a married couple...but since in Michigan blood relatives are permitted to live under the same roof, he could not forbid them from living together as brother and sister. How he intended to enforce that distinction is not clear to me, nor did I ever find out what happened after that.

  With regard to the general topic of incest (and cousin "incest") I think attitudes in the gay community may actually be instructive, since the genetic risk is nil, and everyone knows it is; nonetheless the incest taboo persists. There are those who argue that sex between (male) cousins is incest, and those who think it's perfectly OK. In the fiction written about this they're mostly cousins who haven't seen each other since they were little, removing the family-by-proximity element.

  This is all muddied by the fact that taboo-breaking is eroticized in the gay community; I suspect this arises from the fact that our basic sex drives were taboo growing up, and other taboos get associated with that experience (different ones for different people, of course).

  The result is peculiar in many cases. There's a set of porn videos showing two "stepbrothers" that became quite popular (for reasons not at all limited to the taboo-cachet described above); some people claimed they knew the participants were actually biological brothers and denounced the videos on that basis, which makes no sense to me, but I guess it triggered their taboo-sense in a way the stepbrothers didn't.

  It also seems (from my observation of attitudes among gay men) that the taboo is somewhat lessened if the brothers are identical twins, even though they'd plainly be as close genetically as it's possible to be. Perhaps this is because singleton-born guys can imagine having sex with their own brothers, and react with revulsion; but when they imagine having a twin, they imagine him being themselves, which seems more like masturbation than sex. I'm extremely dubious that actual twins experience each other that way. [They do not. It's usually more like inverse "narcissism": they see their lover in themselves, not the other way around.]