William Saletan defends cousin marriage on the grounds that you aren't that likely to have a baby with a birth defect. I think he's got the problem wrong: it's not an individual risk, but a population risk. Yes, an individual cousin marriage has a fairly low probability of birth defects. But if cousins keep marrying each other, they will reinforce some nasty recessives. That's why small populations that don't outmarry--the Amish, for example--have problems with birth defects, even when they aren't practicing cousin marriage. Whittle your mating population down to a thousand people and you're asking for trouble.
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Whittle your mating population down to a thousand people and you're asking for trouble.
That's three orders of magnitude of my current mating population. My main problem would probably be convincing them to all wear name tags.
Yesterday you were saying that the population risk needn't concern us with concern to polygamy - but today you're saying the population risk of cousin marriage should.
Among the immigrant population from the middle east it is practiced alot and birth defects of various kinds are alot more common among them, so I would not rule it out entirely.
"you're asking for trouble"
as in, Hillary winning your state by 35 points.
It seems like this is a problem that genetic screening should eventually be able to take care of. If two cousins want to get married and they don't share any nasty recessives, then I don't think there should be any legal barrier to prevent them from doing so.
Another way to phrase the question is whether an inchoate social problem that might eventually arise is sufficient to impinge on the liberty of two individuals who truly love each other. Given the nature of the gay-marriage debate so far, isn't that really the only question? Certainly, it's true that in extremely small societies (the Amish) or in small countries inhabited by the same population for several thousand years, cousin marriage might produce a greater incident of birth defects, but has it been tried in a nation of 300 million people, where even the cousin-marrying types are likely to move repeatedly, thus reducing the likely incidence of their children also marrying cousins? If I've learned one lesson from same-sex marriage advocates, it's that concern about this type of speculative societal harm is nothing more than veiled, irrational bigotry (or, in the case of Eddy Elfenbein, not-so-veiled, but extremely funny, bigotry).
Shouldn't you just have saved the trouble and listened to Atrios in the first place. He's long documented the fraud that is William Saletan.
Apparently these folks want to emulate the ripping success of the Pharaohs and Hapsburgs. Good luck with that.
Birth defects aside, shouldn't society have an interest in dissuading the closed/insular communities that result from systematic inbreeding? Saletan's article focuses on recent Pakistani immigrants to the UK. No surprise that new immigrants look within their own group for spouses, which probably doesn't help wrt incorporating into the rest of the community. Now compound that by walling off people who don't share a grandparent. I don't see how that can be a good thing.
Seeing as marriage isn't a necessary requirement for sex, shouldn't the issue be the criminality of cousin incest? If we are serious about trying to prevent this problem of birth defects, we should attach a criminal penalty to instances where cousins have sex, or at least if the sex results in a child (birth-defect or not)?
Of course, this will drive the cousin-lovers underground, creating a rich subculture of cousin-lover bars, hang-outs, etc. I propose that the first bar for this sub-culture be called "Shelbyville".
Should first cousins marry?
If their father's estate is entailed, they should at least give it serious thought.
Richard-
I don't know if it's been tried in a country of 300 million but England, at least, seems embarked upon a test. Their Pakistani-immigrant and immigrant-descended population runs about 50% cousin marriage, and the others tend to be closely related enough that the level of relation is more like 75% cousin marriage.
My understanding is that they suffer from an approx. doubling of the birth defect rate. A health minister brought this up in conjunction with the NHS having to bear the costs and was pilloried for his racism.
There's also the potential problem of the complete lack of assimilation from such an intensely insular culture but I suppose it really would be racist to suggest that replacing British mores with rural Pakistani ones might be sub-optimal.
I do find it amusing that we are considering this from the intensely-western perspective of "two people who love each other and want to marry" rather than from the far more probable "traditional culture of arranged marriages within tribes" perspective.
If two cousins who otherwise live like, say, modern New York cognescenti (ie. they have no centuries-long history of inbreeding in their family resulting in them being more than first cousin related despite 'only' being first cousins and they are not being forced into marriage themseleves and have no plans to force their offspring to continue marrying close relations to insure tribal insularity) then there's prob. no good reason against it. But that's rarely -- if ever -- the case. Far more likely is tradition-bound cultures enforcing their own separatism in lots of ways, one of which is marriage only within the extended family.
It seems to me that there are a whole host of problems societal and otherwise that arise from condoning that, among which is dramatically higher birth defect rates in the practicing population.
Apparently these folks want to emulate the ripping success of the Pharaohs and Hapsburgs.
So perhaps the marrying habits of the Habsburgs (I can't write that with p) are the reason I could marry an aunt or a niece (though no uncles or nephews; but certainly any fears about genetic risks do not apply to them?).
Seletan's point seems to be that if the only practical justification for preventing marriage between close ancestral relatives is the possibility of increased birth defects, the argument is made moot by the fact that women inject an equal or greater risk of birth defects into the population simply by having children at later ages.
With full siblings, the genetic stock is too closely related; with half-siblings, possibly too closely related. Fortunately, we humans seem to have instinctive "kinship detectors" that screen for those sorts of things in a traditional family relationship, preventing sibling incest from becoming common:
http://www.livescience.com/health/070214_kin_detector.html
However, with respect to cousins raised by different mothers, the only compelling argument seems to be "it's traditionally icky", which the so-called enlightened classes reject in regards to, e.g., gay marriage. You can also make a far more compelling evolutionary or religious arguments against gay marriage than cousin marriage, but again, those don't hold much stock for those who want to permit gay marriage, which then comes back to: What is the argument against cousin marriage?
So the increased risk is only an increase from 3 to maybe 4 to 7 percent? Imagine the lawyer feeding frenzy if we learned that a drug, even a drug that saved lives (like Bendectin), increased the risk of birth defects by a tenth that much. The difference, I guess, is that drugs generate profits for greedy corporations, while incest increases one's circle of potential sex partners.
Should you do it? No.
Should there be a law against it? No.
Lost a previous comment on this (forgot to type in e-mail and backpaging didn't help).
Anyway, I don't quite see what you/Megan mean. There is an individual cost to inbreeding. There is a community cost which is the sum of individual costs, but as far as I can see, there's no extra cost. The oposite, actually, since recessives get weeded out of the population and then one can breed together different inbred strains. Since cousin marriage is not likely to be exclusive, the populations will never become too inbred anyway. The problem with the Amish, I imagine, is that they exclusively practise not-quite-cousin marriage. Presumably also founder effects since 15 generations of even 80 individuals would be about as inbred as cousin marriage and I gather Megan is saying they have worse problems than that (I know nothing at all - also haven't read the Saletan article). Anyway, usual finding is that the optimum genetic distance is a bit closer than people intuit in the current generation (although a bit further than cousin, and pretty close to historical norms). A couple of generations of exclusive cousin (or even further) marriage would start to be a big problem, but, again, just an individual one (and then for society too as the sum of that, but I don't see the extra bit I interpret Megan as reffing [I'm a bit confused, in case anyone missed it]).
McArdle, how do you take the leap from expanding the allowable breeding pool by no longer ruling cousins off limits to constricting the allowable breeding pool by preferring cousins or other close relatives?
What on Earth does the first have to do with the second? Do you really think we're all hot for our close relatives, and are only stopped from serious inbreeding by the rules against it?
I don't really have any problem with cousin marriage other than, you know, the world is a big place. Go out and meet other people!
Sure, it's not the best idea; too much of it and you end up like this. http://en.wikipedia.org/wiki/Image:Charles_II_%281670-80%29.jpg
Or this:
http://en.wikipedia.org/wiki/Image:Charles%2C_Prince_of_Wales.jpg
But should it be illegal? No, unless the state is responsible for paying for some people's medical expenses. So, yes.
Mutations occur in closed populations for a reason. Non-related mates imply a large population, signifying nature came up with something right, so there is no need for mutations. But if all you have available to mate with is close kin, that implies that something isn't right and nature tries different mutations until it finds something better. And it's random, not all mutations are good, probably most aren't... but some are good and thus enable the evolution of species to be better equipped to handle the world.
The theoretical cost to society of genetic birth defects is a slippery slope. We can now detect all sorts of recessive genes; should people who have the really nasty ones not be allowed to reproduce together whether they are related or not? Should we start screening people?
You are correct that cousins marrying could lead to an eventual problem in small, insular communities. However, in the population at large, I think the social cost of the government keeping a precedent that it can decide who can and cannot marry is far larger than the genetic cost of two consenting adults possibly perpetuating unfortunate recessive genes.
"Mutations occur in closed populations for a reason."
It's not the the mutations you accumulate per say that are the problem, it's the sharing of defective recessive genes. These genes only cause problems when they are paired with a second copy of the defect. You are far less likely to have similar recessive defective genes with somebody the further away in relation they are from you.
Secondly, in a small isolated population the most likely scenario is that they'll die off. Which is why if a species' population falls below a certain threshold, the odds for recovery plummets.
The issue isn't so much birth efects as the creation of closed-clans instead open-ended family chains. The Middle East practices ciousin marriage on a large scale (though not I think marriage to first cousins) and the result is a fragmented society lacking any unifying personal bonds across it and shot through with suspicion and fear of strangers and neighbors.
Mutations occur in closed populations for a reason. Non-related mates imply a large population, signifying nature came up with something right, so there is no need for mutations. But if all you have available to mate with is close kin, that implies that something isn't right and nature tries different mutations until it finds something better. And it's random, not all mutations are good, probably most aren't... but some are good and thus enable the evolution of species to be better equipped to handle the world.
This is absurd. If the process is random, then there is no directive purpose. If there is directive purpose, then the process is not random. Are you making an Appeal to Gaia here, or are you actually trying to describe an actual dice roll?
I recall a few years ago that the government of Jordan was very happy that they had gotten the rate of FIRST cousin marriage down below 30%. Of course, many of those individuals were already the products of generations of cousin management. This is not a muslim thing but rather is endemic to certain areas within the muslim world, probably based on practices that pre-date Mohammad. There is a logic in that it preserves property in the family.
Quite aside from the genetic issues (which we will all be paying for under HillaryCare II), it promotes ammoral familialism, which is just awesome for integrating new immirgrants.
As hinted above I live in country where marriages between even closer relatives are legal. Nevertheless, the last time I checked the streets of Vienna where not filled with hordes of warring tribal mutants.
Why are you people even HAVING this discussion. The thought of marrying any one of my cousins is repellent to me. I grew up with these people as family members. It would be like marrying a sibling. We live in a large world. What's the necessity for it?
And I come from a Virginian family (that swathe of Appalachia) that has a genetic form of muscular dystrophy that causes, among other things, premature aging. It is
endemic to that area. Two of my mother's cousins died of it in their thirties. We all had to get tested to make sure we didn't carry the gene for it. The reason for its prevalence in that areaaccording to experts at the University of Va in Charlottesville? Three hundred years of inbreeding without much immigration into the gene pool. The only other known area of North America where this particular form of muscular dystrophy exists is in an equally insular community somewhere in Quebec.
I say, thank goodness my mother left the area and married an Irish-Italian.
This an anachronism we don't need to force on ourselves, not only because of the genetic costs but because of the cultural costs.
I agree with holdfast.
I'm all for cousin marriage now and then. It weeds out lethal recessives. Outbreeding without inbreeding just dilutes the problem.
" I think he's got the problem wrong: it's not an individual risk, but a *population* risk. "
Hmm. I thought conservatives were all about denying the relevance of anything population related. Aren't we supposed to despise "quotas" and the ERA and such like because what matters is how blacks and women are treated as individuals, not what the statistics show about what happens to them as groups?
Part of that standard conservative subtlety, I guess, where principle are all important except where they aren't. (vide states rights vs euthanasia; or the "war on drugs".)
Or, to put it differently, god forbid we do anything about the 90% chance that global warming will lead to problems; but it is vitally important that we do something about a problem that has a small effect on most births. We have, for example, the case of Britain which had these sorts of cousin marriages for quite a few centuries and seems to have done fine.
Last time I checked, the US population wasn't clamoring to marry their cousins, so raising the issue of "what would happen if the entire population behaved this way" seems pretty irrelevant to anything.
But, of course, god forbid that we use science, or history, or common sense to view the situation. God forbid we allow some small number people to live their lives the way they want. The important thing is to stand by conservative principles, which apparently consist of ignoring real problems and making up moronic arguments for how to screw up other people's lives.
Did Megan McArdle just make an argument in favor of big government nanny-statism and against individual autonomy in the bedroom?
Somebody please check the sky for flying porcines. And give Megan an envelope; she'll need it to return her libertarian card.
Cousin marriage was the norm, not the exception, throughout most of world history. The antipathy towards cousin marriage is largely a 20th century American phenomenon.
There is a small risk of a concentration of bad genes, but it can also allow the concentration of good genes, allowing beneficial adaptations to spread more quickly.
In any case, I wouldn't advise it, but I certainly wouldn't pass any laws against it, either. Especially where it is rare enough not to cause major problems.
Research shows that "kissing cousins" create more kids, averaging 3.27 kids per couple vs. 2.45 per non-cousined couple between the years 1925 and 1949.
The libertarian/libertine argument for this and other behavious that has a negative population effect works ONLY if the state is not picking up the healthcare tab, so I propose a compromise. If you end the role of the state in providing healthcare, I will let you marry your cousin, I will let you marry you same-sex cousin, hell I will let you clone yourself and then your clone can have a sex-change and you can marry it (or make several clones and have a polygamous marriage) just so long as I don't have to pick up any of the tab for it.
Deal?
The thought of marrying any one of my cousins is repellent to me. I grew up with these people as family members. It would be like marrying a sibling.
Well, there you go -- they are "like" siblings.
On the other hand, one of my own first cousins met an agreeable young man in college and they quickly fell for each other. Upon comparing family records, it turns out they are actually something like second cousins, or second cousins once removed. That outcome is not terribly unlikely in the central midwest, since much of the native population spread out from a pool of French immigrants that mostly arrived between four and seven generations ago. They might even become engaged soon.
Repulsive? Not really. They are both normal, well-adjusted young adults, and they didn't grow up "like" siblings, or even knowing about each other. For that matter, if they knew as little about their genealogies as some people these days, they might have never known there was a relationship at all.
While I understand that your situation has you spooked, you already explained how that came about: 300 years of inbreeding. That's not normal throughout the US generally and unlikely to become normal if the first-cousin ban were lifted. It's not like the native French, famous for their love of wine, sex, and cigarettes (not always in that order), have encountered serious problems as a result of allowing it.
There may be some increased probability of birth defects if they have children, but if the two cousins are in love and willing to accept that risk I don't see any reason to stop them from getting married.
Maynard Handley - Or, to put it differently, god forbid we do anything about the 90% chance that global warming will lead to problems
The chance that increased CO2 will actually cause significant catastrophe are actually pretty low. The argument among scientists usually runs that because the danger might be so catastrophic and so high, that we'll reach a tipping point, so we should do something even though such a catastrophe is unlikely. It'd have to be pretty catastrophic to justify the massive regulation and (environmentally harmful) inefficiencies that such regulations would create.
"The chance that increased CO2 will actually cause significant catastrophe are actually pretty low. "
Especially when whatever happens is explained away as not actually being caused by global warming.
Hurricane in New Orleans? Random coincidence.
Hurricane in Burma? Likewise.
Below average food harvests? Well these things fluctuate.
War between India and Pakistan over water because of insufficient snow in the Himalayas? Heck, those two have been at each other's throats for 60 years.
etc etc etc
I see Mssr Handley doesn't follow hurricane news too closely. In 2005:
http://archive.newsmax.com/archives/ic/2005/9/25/131154.shtml
In 2007:
http://www.scientificblogging.com/news/global_warming_may_mean_fewer_hurricanes
This week:
http://www.technewsworld.com/rsstory/63066.html?welcome=1211435458
In short, the jury seems to be out on this one, but leaning slightly negative on the traditional GW alarmist take on the hurricane equation, i.e., hurricanes may be more intense in response to warming, but we get fewer of them.
If the AGW deniers have a problem of explaining away everything as not actually being caused by global warming, the most charitable thing that can be said about the AGW alarmists is that they have the opposite problem: everything is evidence of global warming.
Also, I see the sunspot count is still at zero as of 5/19:
http://www.spaceweather.com/
Which leaves us wondering what to do about this guy:
http://www.theaustralian.news.com.au/story/0,25197,23583376-7583,00.html
If by some chance he's right, I wonder what link to human activity Gore will need to come up with in order to avoid losing his messianic street cred. Sunspot inhibition is caused by....oh, HDTV broadcasts, maybe? The new beacons lighting up in the US market in anticipation of the Feb 2009 FCC analog cutoff are about to Freeze Us All, and we need to give up our decadent, entertainment-soaked ways at once and submit the power to Do Something to our eco-friendly social-political superiors?
Well, you're right that small breeding pools mean recessives have a greater probability of reinforcing --- although, if you want to use that argument, you ought to note that it's also a fine way to ensure that recessives, especially for fatal conditions, are eliminated from the gene pool.
The notion that this has anything to do with whether first cousins in a general US population of 300 millions ought to be restricted from marrying seems, well, a bit of a stretch.
I think a lot of people are approaching this without an historical perspective.
Fact is, most of the human race has been traced back to six (yes 6) women. As in that's all folks. So we have always been inbreeding, if you will.
Second fact is, up until the industrial revolution, most of the human race were inbred in another sense. You, your best friend, everybody married cousins. Not only did the agrarian lifestyle diminish the number of partners and transportation costs reduce the freedom to find new people, but early death rates (due to lack of medicine, not inbreeding) and young, religious marriages kept any new suitors from finding many willing takers even if they did hit up a new community. Finally, marriage was very class based back then; if your family was the only royalty around, they were the only ones you COULD marry. Ditto for poor people.
Third fact is, the attacks on the Habsburgs for being inbred and stupid is largely a by-product of the victors writing history. The Habsburgs were powerful, but disliked; therefore, attributing their downfall to their being foolish and retarded is well within keeping with the human tendency to libel your enemy. More recent examples: Hitler had one testical; kim jong-il has a napoleonic complex; Osama Bin Laden has a small penis.
In Shakespeare's time, caricatures of the Spanish Kings and French leaders as sadists, sexual perverts, or deformed creatures was commonplace. Remember that the only records we have of Richard III being a hunchback/withered hand child-killer are from Thomas More and other writers who were writing from the perspective of Richard's enemies' descendants.
Did the Habsburgs inbreed? Yes. Did they inbreed more or less than the royal families they feuded with? No. But when their dynasty collapsed, so did their lawyers and propagandists; the victors never lost theirs.
More importantly, our modern conceptions of inbreeding are largely a product of the Civil War and its aftermaths. Southern families still followed an agrarian lifestyle, whereas Northern families were more industrialized and were in more urban populations. Naturally then, Northern propaganda against the South fixated, partially, on inbreeding and stupidity; Southern, on the filth, immorality, and decay of a city.
This propaganda was revived during the civil rights movement, often as more than just tongue-in-cheek rationale for Jim Crow.
Thanks all.
Sorry to sounds politically incorrect, but the practice of marrying cousins, coupled with the practice of polygamy, leads to the treatment of women as means rather than ends, and also sets the stage for large groups of disenfranchised males, which is the one universally recognized risk factor for war.
Check out this map:
http://www.consang.net/index.php/Global_prevalence
heart of Europe,
As hinted above I live in country where marriages between even closer relatives are legal. Nevertheless, the last time I checked the streets of Vienna where not filled with hordes of warring tribal mutants.
Yeah, but given Austria's current native birthrate (in 2006, 8.81 births per 1,000--well below the overall EU rate of 10.2), and immigration rate, in 50 years the streets of Vienna will be "filled with hordes of warring tribal mutants." And they'll be Muslim. And Vienna will by then will have been renamed "Al-Vindabona."
Verstehen Sie?
There seems to be a lot of posting that is unfamiliar with basic genetics. All the inbreeding in the world will not cause a recessive gene to die out. In fact, assuming the gene in question were lethal, and the lethality manifested itself prior to procreation, the gene would still persist in the population at a stable rate. Two heterozygous ( one affected gene one normal gene) individuals mating would produce on average 25% homozygous (both genes the same) normal individuals, 50% heterozygous carriers, and 25% with the genetic abnormality in question. Even if all of the affected individuals died, as long as there is an aymptomatic carrier state, the gene will persist indefinitely. Examples of this type of defect include Tay Sachs and Cystic Fibrosis. Tay Sachs, despite being lethal by age 2 and being relatively prevalent in certain Jewish Communities has been a stable recessive gene.
The comment by Alan:
"There is a small risk of a concentration of bad genes, but it can also allow the concentration of good genes, allowing beneficial adaptations to spread more quickly."
is incorrect. Inbreeding will not allow adaptations to spread more quickly because 1) inbreeding delays the spread of a gene through the general population (ex Tay Sachs) and beneficial adaptations increase in frequency only in relation to their conferring a survival advantage. If they do have such an advantage, they will increase infrequency, inbreeding or not.
Additionally, even if the statement from Jack Mitchel that there were originally only 6 women were true, the mutations which have taken place over the centuries have created a much more diverse gene pool which is inherently safer from a genetic point of view than if we were to try to inbreed from a small number of individuals. In point of fact the following link suggests that most Native Americans (not all humans) were descended from 6 women.
http://www.usatoday.com/tech/science/genetics/2008-03-13-native-american-dna-roots_N.htm
MarkJ,
As an Austrian chancellor remarked, the population is not growing through the vigor of Austrian loins but through immigration from the Balkans. So as long as there is one ex-Yugoslave for every Muslim coming to Vienna you can relax. And of course there are also all those German students fleeing the numerus clausus.
Btw, why should they choose the arabisized Latin name?
I married my first cousin, and we had 3 children. The oldest just graduated, and is going on to graduate school in physics, with a Goldwater Scholarship. Her number 1 younger brother is getting his undergraduate degree in physics, her number 2 younger brother has just graduated from high school and will go into the medical field.
Of course it helps that my first cousin is brilliant summa cum laude material working as a physician-assistant, whereas I am, at best a very good reader with A-B college grades.
My point; It matters more who you marry than nearly any other decision you can make. Who is more important that what class into which they fall.
My grandfather's degree was in agriculture/animal husbandry. He never spoke of any concern in the slightest for interbreeding between cattle that were as closely related as cousins. He did have bad results when once, through inattention, there was a brother-sister breeding.
Rob Lyman: "If their father's estate is entailed, they should at least give it serious thought."
Sorry Jane Austin fans, entail was abolished in the US in the 19th century for the same reason as cousin marriage was banned. To limit dynastic accumulations of property. [note the UK did it in the 1920s]
Holdfast noted that cousin marriage in the muslim world: "is not a muslim thing but rather is endemic to certain areas within the muslim world, probably based on practices that pre-date Mohammad. There is a logic in that it preserves property in the family."
Which is correct. Cousin Marriage in what is now the Muslim world predates Islam by a long margin.
The bottom line is that cousin marriage was banned for the same reason that entail was, not for genetic reasons, although genetic reasons are another reason why the bans should remain in place.
It's interesting to compare this current controversy with the historical marriage patterns of British people; in particular, the upper and upper-middle classes throughout much of the early-modern history period.
Cousin marriage was not unusual for centuries; up until the early 20th century. This practice also occurred in Europe as well. One motivation was based on the desire to keep all of the family wealth (in particular, land) within the related branches. I don't believe anyone has researched any possible connections to increased birth defects; but among the European royals such evidence is available. The Hapsburgs and other royals intermarried frequently and produced several famous examples of major birth defects and re-occurring genetic problems.
America also practiced cousin marriage throughout the 1800s. While it survived longer in the most remote communities; if you examine the marriage patterns of the wealthier families, the prevalence is evident. This pattern in elites wasn’t due to a small local population, but rather to the same desire to preserve family assets and to marry within certain select social circles. Keep in mind that cousin marriage was socially acceptable, and the scientists of the day lacked our knowledge of the genetic dangers. Therefore, cousins were considered eligible marriage candidates.
Finally, these people didn’t experience the mobile lifestyles of our population. Remaining within a more limited geographic area meant more frequent contact within the extended family members. Hence your cousins were often close friends; building emotional intimacy from an early age.
With the absence of social and medical disapproval, the encouragement from elder members of the family, and the experience of early emotional bonding with cousins; the resulting environment led to marriage.
Basing British governmental decisions on antiquated marriage patterns or Pakistani marriage practices, however, does not justify risking the future health of British children.
Suttee was also an antiquated marriage practice in India centuries ago. Should an Indian immigrant now argue that Britain should allow their wives to begin burning themselves alive at the funeral of their husband? This barbaric custom was an expected, accepted part of marriage two centuries ago. It decision made between family members; but the British government ended the practice to prevent harm to women.
If Britain wants to rely on the argument that "this is only a cultural and religious decision, therefore, everyone should respect their right to marry whom they wish"; they risk turning the clock back on a century of improved medical advances that protect the health of children.
ragnell
This place is bad for my health. aemd is wrong and ignorant, and his attitude in his ignorance is annoying. Why do you think our well known strains of mouse are just about 100% homozygous? Can you put that together with the consequences of inbreeding on lethal recessives? Listen, if you're a kid, no problem. Indeed, I suggest you try drawing a little tree out in which you look at the gene frequencies over generations with repeated inbreeding. You might also think about the various reasons your examples are not relevant.
If you're an adult - there's a reason you never made it in life, you fucking moron (making the dubious assumption of a just universe. Feel free to delete my post, Megan.
Re: Cousin marriage was not unusual for centuries; up until the early 20th century.
Marriage of first cousins was against canon law going quite far back, so that form of cousin marriage was rare in Christain countries. Og course, marriage to more distant cousins was permitted and may have been common, especially among the rarified upper strata.
Re: The Hapsburgs and other royals intermarried frequently and produced several famous examples of major birth defects and re-occurring genetic problems.
The Spanish branch of the family (which did intermarry with French and Portuguese royalty) did suffer this problem and died out in the late 17th cebtury, but the Austrian branch of the family was free if such trouble and is still around (minus the crowns) and healthy to this day.
I've an in-law who is the product of a first cousin marriage. He's one of five siblings, three of whom suffer from Usher's Syndrome: their hearing was lost by the time they reached adulthood, from then on they gradually lost all peripheral vision. Anyone who says there won't be birth defects certainly hasn't done much research.
K Winterer at 8:19:
Straw man. no one says that inbreeding wouldn't produce birth defects---but even non inbreeding produces these effects. By that argument, no one should breed if there is any chance of birth defects. which means no one.
Second, the point is that the percentage increase isn't that great, and the state shouldn't be punishing those who do it. The state can offer incentives to those who do not inbreed and encourage it. But social taboos mostly keep people from doing it in the first place.
This is not an individual rights issue. There are 2 major issues here:
1) The first cousin marriage, I agree, doesn't cause a major problem, genetically. But to allow the continued inbreeding to continue over generations is nuts. It leads to less and less diversity, over time, in that small population, with the associated birth defects.
You can't just screen for problem genes. We don't know most of the genes that cause defects, nor do we have a real understanding of the majority of genetic defects. Unanticipated problems will arise from the restricted gene pool. One of those problems is that damage to a gene is a more serious event than it is in a larger gene pool.
2) The second issue is that many of these "family" marriages occur because the elders tell the couple to marry - regardless of the preference of the two (or more, in the case of polygamy) involved.
In the US, we have a long tradition of individual choice in marriage partners. These marriages don't happen because two crazy kids fall in love - to quote Tina Turner, "what's love got to do with it?" Since so many of these marriages are arranged, with little opportunity for personal choice, they are, in a very real way, un-American.
Now, how are these arranged marriages different from those of many Indian-Americans, who also have a long tradition of arranged marriage? The element of coercion is the distinguishing feature. There is strong evidence that many young women are threatened, assaulted, and forced into agreeing with the marriages. Some are even taken to another country, sometimes before they can be legally be married in this country, to be forced to marry. Their options are limited to non-existent in those other countries.
It amounts to prohibiting cousin marriage for two factors - genetic diversity and avoiding the probability of coercion (whether mild or forcible).
Are you people ever reading the source material?
"If we are serious about trying to prevent this problem of birth defects, we should attach a criminal penalty to instances where cousins have sex, or at least if the sex results in a child (birth-defect or not)?"
I guess you also support criminal penalties against woment over 40 having sex or producing a child with Down's Syndrome? After all, age is the single most important factor in many congenital defects.
"The thought of marrying any one of my cousins is repellent to me."
Then don't do it.
"This an anachronism we don't need to force on ourselves."
Somehow I missed the part where marrying your cousin would become manditory.
I don't see how allowing someone to marry their first cousin, should they choose to do so, poses a great threat to society or the health system. Yes, they may be taking a risk with their children, but so do millions of people with family histories of genetic conditions or who become pregnant with specific risk factors (age, history of smoking/drinking, etc.). The ability to live your life and choose what risks you will take is paramount in the question of freedom.
The only valid question, I think, is the degree to which cousin marriage in a distinct community (e.g. British Pakistanis) goes beyond being cultural and into the realm of forced. This, however, is still a question of freedom and is really no different than many other situations in which minorty women are insulated from their due freedoms in a Western society by their own culture. This concern, however, is not specifically limited to questions of marriage.
Senators are proof positive of what happens when cousins pro create.
aemd - There seems to be a lot of posting that is unfamiliar with basic genetics. All the inbreeding in the world will not cause a recessive gene to die out.
Two heterozygous ( one affected gene one normal gene) individuals mating would produce on average 25% homozygous (both genes the same) normal individuals, 50% heterozygous carriers, and 25% with the genetic abnormality in question.
1. I didn't claim that inbreeding would cause a recessive gene to die out. But if the recessive gene is a truly lethal homozygous
Of course, a few genes seem to be beneficial in the heterozygous form but harmful if homozygous. Inbreeding would remove those too.
Plenty here about physical defects. Does anyone have a view on the psychological effects of close marriage over many generations, e.g. narcissistic and perfectionist behaviours seem pandemic these days. The preoccupation with physical deficits arising from cousin marriage suggests an ironic obsession about superficial perfection. How healthy is this? Is it becoming increasingly difficult for us to tolerate natural imperfections and increasingly easy to tolerate the bizarre antics of those who believe they have a "divine" right to father their daughter's children, for example?