Don’t laugh. According to this New York Time story there’s hardly any genetic risk to it.
Frankly, I still think marrying your cousin is kinda, well, strange, but maybe that’s just because I believe in the same fallacies the authors of this study point out.
Are there and Dopers who are married to their first cousin, wanted to marry one, or have family members who are? Your input would be greatly appreciated.
I confess to being the child of first cousins. (So are my sisters!)
My posts on SDMB make it clear that the Journal of Genetic Counseling overlooked some of the risks… 
I think a better question is “How can you possibly justify telling two consenting adults who they can and can not marry?”
Hell, if brother and sister wish to marry, let 'em.
But even the authors of the Kissin’ Cousins study say that bro and sis unions would cause a significant increase in the risk of birth defects to their offspring.
Also, brothers and sisters are so genetically similar, that allowing them to marry and have children goes against that whole “genetic diversity” thing.
We can justify telling them they can and cannot marry because it puts their eventual children at far too much risk and is detrimental to the gene pool overall. The same goes for mothers or fathers marrying their own children (Which, Beelzebubba, you would seem to also support, according to your post.)
So, if they were to have any children, the potential children could possibly (a big possibility) have birth defects.
Um…so what? At what point does it become your right to tell two people what they can and can not do as consenting adults? Unless these potential children are destined to become wards of the state, what business is it of yours or the society in general?
Given your “gene-pool” analysis, would you support late pregnancy abortions to avoid detrimental effects to the gene pool? May be that’s not a fair comparison, as we’re dealing with already-conceived and developing children.
How about preventing those with genetic disorders from having children? As we are concerned about the gene pool, and it appears to be our collective responsibility to ensure its integrity, we prevent those (for example) who are HIV positive from reproducing? What about those with sickle-cell anemia, should we prevent couples who both have the sickle-cell trait from pairing up?
Where does it end?
It ends (and starts, I guess) when we are dealing with people who already have an established genetic and familial (sp?) relationship. While the above groups you mentioned certainly have genetic risks, making laws against them mating would require great intrusions into their privacy (for one, it would clearly violate the right to have medical records kept private). The risks (shattering a right to privacy) would not be worth the benefits (a slightly tidier gene pool). But family relationships are a matter of public record. Making laws against such forms of incest is not as intrusive as laws dealing with other such groups.
Also, I think one would be hard pressed to find a modern society that supports marriage between full siblings or parents and children. This is because incest can cause psychological havoc not only on the participants but on entire families. Two unrelated people with genetic disorders having children may cause some sort of medical malady, but it would likely not taint a family on a physical and mental level for generations to come.
The family is the foundation of any society, and society has an obligation to protect its integrity. Incest on such a level is clearly a threat to that integrity, and that is why I believe society and the government has a right to do what it can to prevent it. The risks in allowing it are far, far greater than allowing unrelated people with genetic disorders to have children.
I like the points made by SNenc but I think that the right to privacy has nothing to do with it. It is the right to self-determination that we are talking about. It is not the right to privacy it is the right of people to decide what to do with their lives.
Let them do whatever the hell they like.
What if, in such couplings, both participants willingly choose not to have children? Not everyone marries for the sole purpose of breeding. Then, the whole genetics issue is out the window. Would you (or anyone else) be opposed to a childless marriage?
While you make a good point, and the cousins thing doesn’t really bother me, I start to twitch rock, and hum (with my fingers in my ears) when I think of a parent marrying his/her child, even with no children involved (I’m assuming, here, that there is still sex involved, and that both parties are aware of the familial bond, i.e., we’re not talking a random meeting between an adopted child and a biological parent or something).
I guess people should still have the right to do what they want, but the ICK factor on certain unions is just too high for me…
Sig line!
Also, what happens the offspring of such a union-with a long history of inbreeding-goes and decides to break the tradition-and these genes get passed along and cause all kinds of havoc?
Didn’t we learn anything from looking at some of the problems of the royal families?
It seems that some people have the ICK factor and some don’t .I’m wondering if the difference could be explained by how people were raised. Take my family, for example. I have the ICK factor, and I don’t think it has anything to do with genetics (and I’m not saying it should have anything to do with the law).I actually know some of my maternal grandfather’s cousins’ grandchildren. I know all of my maternal grandparent’s siblings’ grandchildren fairly well. Some of my maternal first cousins lived next door when I was a kid, and I saw the others two or three times a month. I’ve gotten the impression that not only is this very uncommon, but that it’s even pretty uncommon for people to know their first cousins well. So, any Dopers with first-cousin marriages in their family, could you also mention where they fall on the “practically raised as siblings” to “once a year visitors” line?
Doreen
Did you ever read a post where the entire sequence of a horribly contorted thread finally becomes clear? I just had one of those for what’s happened to all of Great Debates!
Seriously, my grandparents took in their nephew when he left home (on a farm) to work for the railroad (which my grandfather also did). He lived with them until their deaths and, after they died, with their unmarried daughter, my aunt and his first cousin, who took care of them in their old age. They were quite close emotionally, and after his retirement, when he found that he could leave her his pension only as his wife, he proposed, they married and had a happy year – and he died eleven months later, one day after her pension rights as his wife kicked in.
Sorry, Guin, but as I undertand it, that’s a popular misconception (no pun intended). Hemophilia – if that is what you’re referring to – is not a recessive gene trait, but is carried on the X chromosone.
The marriage of first cousins is pretty common in other societies, particularly Asian, and hasn’t resulted in inordinate amount of genetic defects.
You’ll have to argue this one strictly on cultural grounds.
Yes.
So what you’re saying is that my (hypothetical) son should be able to marry my sister’s (quite real) daughter.
No. I don’t think so. Take that one to somebody else’s legislature.
As anyone who has met my cousins can testify. 
I don’t see why marriage has to be about procreation, like they’re doing their duty to the party. Even assuming I did want to marry one of my three very beautiful cousins, what makes us compelled to have children? At least one of them has no interest in having a child at all.
(Disregarding JonScribe’s most recent post… until cites come flyin’ in because I wish to subscribe to those newsletters) Does anyone feel that first cousin’s having children is morally indefensible? What about Gataca-like scenarios, could we scan the blood from the tests demanded by marriage and dictate who can and cannot have children based on the likeliness of congenital defects the child would have? In what way is one ban really any different than the other?
If it makes you feel any better, erl, I’ll let you marry my sister’s daughter . . . in about 18 years.
Very common in many Moslem countries - helps to keep wealth in the same family. I heard it’s legal in the UK.
Marrriages between first cousin are legal as well in France. And though they aren’t particulary common, they aren’t frowned upon at all. There’s no “eek” factor about them. I guess as usual it comes down to what people are accustomed to rather than to objective reasonnings.