Since the whole marriage equality debate started I have been wondering why siblings (whether it be brother/sister, brother/brother, sister/sister) are not allowed to marry. Two consenting adults should be allowed to marry whom ever they choose. In line with that, why shouldn’t they be allowed to have children? Yes I realize that there is an increased chance of birth defects but there is also that risk in women over 40. Women who also carry the recessive gene for breast cancer can have children (Agelina Jolie)
Are you asking honestly or is this one of those “gay marriage is a slippery slope to the end of civilization” things?
I am truly curious. I’ll also make it clear that I am happily married to my husband who is of no relation to me.
Does this question have a factual answer? If I were king of the world, any consenting adults would be allowed to marry. I wouldn’t even limit it to two.
There are two theories, pick which one seems more convincing to you:
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Some claim that the prohibition of incest (and incestuous marriages) exists for survival reasons. Inbreeding leads to high rates of birth defects, and human beings are designed to avoid things that weaken the long-term survival of their genes. This natural repulsion still exists today
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The other option is that this prohibition is a social thing. Back in the day, a man marrying his sister would have been bad for community diplomacy. After all, why marry your daughter to your son when you can offer her to someone from another community in exchange for favours/aid? This taboo still exists today.
Thank you Batistuta your answer makes a lot of sense without being a jerk about it.
The community has a vested interest in prohibiting certain kinds of marriage, primarily those that pose a risk to the community or its members. With incest, it’s really difficult to ascertain that both members are really willing and equal partners, because family dynamics are so complex. If each person in a marriage comes from an independent family, there are more likely to be interested outside parties ensuring that the dynamic isn’t TOO screwed up.
The historical origins and “OMG the (potential children)!” are also factors, but since once is the appeal to tradition and the other can be mitigated by science (genetic testing etc.), I don’t think they are the sole criteria.
Your analogy of women over 40 and parents with a cancer gene doesn’t hold up well, because it doesn’t take account of the cumulative risk over generations. If I have kids at 40, and my kids have kids at 40, and their kids have kids at 40, those great-grandkids’ risk of a genetic disorder isn’t any higher than my kids’ risk was. The same goes for risk genes: if I carry a risk gene, my great-grandkids’ risk of inheriting it isn’t any higher than my kids’.
But if you marry your brother, and then your kids marry each other, and then their kids marry each other, your great-grandkids are in way more genetic trouble than your kids were. So a society that allows sibling marriage is likely to have more and more genetic problems as time goes on, while that’s not true for a society where women have kids past 40 or where people with risk genes have kids.
I don’t know if that’s the reason for the prohibition on incest - just pointing out a flaw in the argument.
While there are factual reasons for the incest taboo, since the question involves “should” this is probably better suited to Great Debates.
Colibri
General Questions Moderator
Yes I had thought about that and didn’t have an answer for that outcome. In the same sense if you are gay and your kids are gay and their kids are gay… wait that wouldn’t happen because you can’t reproduce.
Careful there. Your agenda is showing.
I think its mainly inertia. Back when people lived in smaller communities with larger families, and inheritance of land mattered more, there was more of an incentive to look at siblings as possible spouses. And so the incest taboo was reinforced by making it a leagl principle as well.
Nowadays, there probably isn’t really much need for the law, as I doubt many people would be interested in marrying their siblings in anycase, and we have the medical technology not to worry overly much about a few extra birth-defects if they do. But by the same token, there isn’t really any community of people that cares about the law staying on the books, so I doubt it will go anywhere.
Let’s not lose sight of the fact that all those homosexuals come out of heterosexual unions.
Pretty clearly that’s who should be stopped!
Historically, societies with sibling marriage have done so to keep land and power within a small family group, so anti-sibling marriage laws are sort of anti-trust laws. Yes, Royalty tends to marry royalty, or at least nobility, so the power still stays within a large extended family, with a weird chin and hemophilia as a result, but it does provide a bit of check and balance. The Pharoahs had a strangle-hold on Egypt for a while, with sibling, and parent-child coupling, to keep the wealth in the nuclear family.
BTW: in a country like the US, a brother and sister from parents of diverse backgrounds have less chance of having a child with a genetic defect than second cousins once removed from an isolated community where everyone is descended from the same 8 people, with maybe one outsider added every generation, for the last 150 years.
No relation? That’s not true. Look at it realistically. You’ve got two parents, and four grandparents, and eight great-grandparents, and sixteen great-great-grandpoarents, and so on, and so on, and assuming 25 years per generation, when you get back around 800 years you and your husband both had more than a billion ancestors each if there was no overlap between any of them, more than the population of the Earth.
What you mean to say is that your husband is of sufficiently distant relation that you’re not squicked out about it, and the same is true about your ancestors, who were also undoubtedly distantly (you hope) related.
If we’re going to have same-sex civil marriage, as seems rather inevitable, then I would much prefer opening civil marriage to siblings and parents and children as well, in order to make it perfectly clear that civil marriage no longer has a romantic/sexual implication, but is simply a legal contract.
Others have pointed out this apparent paradox. It’s pretty hard to argue against the logic that people who are inclined to heterosexuality are going to reproduce more than people who are inclined to homosexuality. So why doesn’t homosexuality disappear due to natural selection?
One theory is that the genes that cause homosexuality also cause other other good survival traits. So the genes get passed on because the benefits of the good survival traits outweigh the cost of reduced reproduction rates.
I do not understand why same-sex marriage would lead you to this conclusion. It seems that either you are going to extraordinary lengths to avoid thinking that a given couple might be in a same-sex romantic / sexual relationship, or else that you want to make sure that any rights gained by the gay community are immediately rendered meaningless. This is called cutting off your nose to spite your face.
Just so you know, this is not always true.
Are you a boy?
As to why sis and bro can’t get married, You know, the real legal reason why… I don’t know. I can guess, but I don’t know.
I bet it’s similar to the alleged voter fraud problem: It’s not an issue because almost no one tries to do it.
Just my guess, I return you to the professionals…
That may be true, but there could be two other reasons that homosexuality didn’t die out:
First, relatively large families. If your family caries the “gay gene” and you have a child that is homosexual, your 3+ other children who aren’t homosexual have a 50% chance of passing that gene on to their children. (Percentage assuming it’s a simple Mendelian characteristic with a dominant and recessive version.)
Second, it could be a large collection of genes that influence sexual behavior. On their own, each allele is harmless and/or beneficial to the species as a whole. When these genes interact, they lend an increased chance of homosexuality. Thus, all of these getting passed down and only those that hit the right combination get to open the safe, as it were.
Personally, just because of the variety of both sexual attraction and sexual behavior out there, I tend to lean towards the second.
In addition to the fact that we placed a lot less importance on romantic attraction before the mid-19th century. So women, even if inclined to the same sex, would marry a man and have children sometimes because they needed to for monetary and social reasons, and sometimes because they didn’t have much choice. And men would marry a woman and have children because it was expected of them for social and dynastic reasons, but then secretly have men on the side.