Banning incest - natural reaction or stuffy old morals?

[truehobbit]

Yikes - I had no idea such a thing could exist!

Thanks, LordM.

[vison]

Consenting adults should be left alone, but the issue is "consent". Often there are power imbalances, hell, there are power imbalances in "normal" sexual relationships!

As I said on another forum, there have been societies in which brother/sister marriage was common in royal houses, for instance in Egypt and Hawaii. Others, too, I believe. These marriages not only maintained the "purity" of the line, but kept interlopers from the throne. The kingdoms that carried on this practice were, perhaps, insular and "complete", not seeking expansion through marriage.

On the other hand, the taboos on incest seem to be very old. I wonder if at least part of the taboo was the recognized need for mates "outside" the clan? Not so much the observation of genetic abnormalities, which often take several generations to turn up, but rather the strength of ties between groups, creating alliances and extending power bases and properties. Siblings marrying bring nothing new of value to the marriage and we mustn't forget that "marrying for love" is a pretty new idea.

Don't get me wrong, I'm not arguing FOR incest, not at all. I think it must be very unlikely that two mature consenting adult siblings actually decide to mate. And if they are not "mature consenting adults", well, then we are back at square one.

[Túrin Turambar]

If they are not mature or consentingl, then there are issues beyond simple incest.

[Crucifer]

Incest is wrong... Really disgusting, IMHO.
I mean, if God had meant us to have babies with our sisters/brothers, then he wouldn't have created the genetic abnormalities that are rife with it. Therefore, sexual intercourse with a relation (third cousins and beyond is O.K., as that is pretty distant) is also pretty wrong, as the whole point of sex is to reproduce.

[Frelga]

The WHOLE point? Well, sheesh!

If the God had meant the WHOLE point of sex to be reproduction, she wouldn't have made it possible for people to have it unless they were fertile. Or made it so much fun in the first place.

[truehobbit]

If the God had meant the WHOLE point of sex to be reproduction, she wouldn't have made it possible for people to have it unless they were fertile. Or made it so much fun in the first place.

Well, (getting away from God here ), given that nature made reproduction the most important thing for any living creature, I think any incentive to engage in it is useful.
And that's the reason it's fun.
And, most people do have more sex while they are fertile. I think it wouldn't be possible to have the sexual urge like an on/off button, making it impossible to have sex if you're not fertile. On the contrary, it's much more useful to have sex once too many than once too rarely, i.e. nothing wrong with giving it a try when you're not fertile.

In short, I'm afraid I agree that all that fun is just for the passing on of our genes - and I agree that the fact that this goes wrong more often among close relatives is nature's way to ensure diversification.

Although, if looking at it from a more spiritual perspective, and assuming God created it to be fun, I'd agree that that's a perk.

(When I just saw this thread up again, I didn't even remember I'd started it. )

Btw, welcome to HoF, Crucifer!

[Crucifer]

O.K. God aside.
If in the natural course of things it was meant for me to go have sex with my sister, then there would be no increased chance of disability etc. Because the only purpose of sex is reproduction (it is fun so that it gives us an incentive), this means that nature meant us to never have sex with siblings.

[Frelga]

Well, (getting away from God here

You can't get away from God!
<-- this guy tried.

OK, sorry, Hobby, I'll be serious now.

And, most people do have more sex while they are fertile. I think it wouldn't be possible to have the sexual urge like an on/off button, making it impossible to have sex if you're not fertile.

Actually, this is how it works for most mammals - the females are only sexually active when they are fertile. I think apes are the only ones who have a menstrual cycle instead of the estrous cycle.

I am sure that it has a survival value. Maybe it's because a human (or an ape's) child takes so long to mature, that having it in the right season is less important than making as many as possible whenever possible. Still the fact that we ARE capable of having fun without making babies suggests that this activity has other survival properties. It serves to reinforce bonds between the couple, relieve stress and generally make life better. And to make babies, of course.

In short, I'm afraid I agree that all that fun is just for the passing on of our genes - and I agree that the fact that this goes wrong more often among close relatives is nature's way to ensure diversification.

I'd switch the cause and effect around. Diversification helps reduce the chance that two recessive genes will come together and make trouble, as is indeed more likely to happen with close relatives. However, it is entirely possible for a baby to have a genetic defect with parents who are not even remotely related.

Which brings up a question that I'm sure has been covered here already - if the increased risk to offspring is a valid reason to make marriage illegal, how far should we take this? Should people with diagnosed genetic defects be prevented from entering into marriage?

Or looked at another way, is it OK for siblings to marry if they undergo genetic testing and are found not to have any defect-producing recessive genes lurking in the background.

Although, if looking at it from a more spiritual perspective, and assuming God created it to be fun, I'd agree that that's a perk.

ITA

Edited for unfortunate wording.

[Crucifer]

Which brings up a question that I'm sure has been covered here already - if the increased risk to offspring is a valid reason to make marriage illegal, how far should we take this? Should people with diagnosed genetic defects be prevented from entering into marriage?

Of course not.

[truehobbit]

Crucifer, yes, I think I'd agree, although I wouldn't say there are such absolutes.

Well, (getting away from God here

You can't get away from God!
<-- this guy tried.

Ok, let me put it differently: getting away from blaming God for our sex-life

Still the fact that we ARE capable of having fun without making babies suggests that this activity has other survival properties. It serves to reinforce bonds between the couple, relieve stress and generally make life better. And to make babies, of course.

I don't think it's like that very much.
Just because it happens that you can have sex without getting pregnant doesn't mean that sex has any other reason but to become pregnant. The sexual desire itself, IMO, has no other reason but to create a new specimen and if you don't get pregnant after sex, then the attempt failed.

I do agree, however, that our capacity to feel pleasure from sex has a variety of reasons beyond being an incentive to try more often, but they have more to do with our state of development, our different level of socialisation, for example, compared to (as far as we can tell) all other creatures in nature.
So, yes, reinforcing the bonds between a couple is certainly a bonus result, too.
Stress relief, too, will help with survival.

So, yes, there are a whole lot of explanations why sex to us is not the random act it seems to be in most of the animal kingdom - but that doesn't mean that the sexual act itself isn't still purely for the purpose of the continuation of the species.

In short, I'm afraid I agree that all that fun is just for the passing on of our genes - and I agree that the fact that this goes wrong more often among close relatives is nature's way to ensure diversification.

I'd switch the cause and effect around. Diversification helps reduce the chance that two recessive genes will come together and make trouble, as is indeed more likely to happen with close relatives. However, it is entirely possible for a baby to have a genetic defect with parents who are not even remotely related.

I don't see how the fact that genetic defects can affect anyone switches cause and effect.
I think the reason we are attracted to certain people is because our instincts try to guide us to certain gene-qualities. If few women feel attracted to pallid, hunch-backed guys that's not because society has developed unfair prejudices and beauty ideals, but because our instincts cry out 'bad genes'.
Diversification is one way to keep the gene pool from becoming muddy, so that's where our instincts go, too.
(Of course, on the other hand, they also tend to go to something 'alike' to us.)

Which brings up a question that I'm sure has been covered here already - if the increased risk to offspring is a valid reason to make marriage illegal, how far should we take this? Should people with diagnosed genetic defects be prevented from entering into marriage?

Yes, I think we covered that - but I still couldn't answer the question.
(I also think that, in addition to increased risk to offspring, there are other aspects to come into a decision on sibling marriage.)

Or looked at another way, is it OK for siblings to marry if they undergo genetic testing and are found not to have any defect-producing recessive genes lurking in the background.

I don't really know about this, but I've always thought the problem with genetic defects from sibling reproduction is not so much that there is greater risk of defective recessive genes becoming active, but that the defects produced are spontaneous, maybe as a result of the similarity of the material. So, even if both partners did not have any such genes as you say, the risk of producing children with genetic defects would be higher.
But, as I said, I'm not sure that's correct.

[Crucifer]

Or looked at another way, is it OK for siblings to marry if they undergo genetic testing and are found not to have any defect-producing recessive genes lurking in the background.

I don't really know about this, but I've always thought the problem with genetic defects from sibling reproduction is not so much that there is greater risk of defective recessive genes becoming active, but that the defects produced are spontaneous, maybe as a result of the similarity of the material. So, even if both partners did not have any such genes as you say, the risk of producing children with genetic defects would be higher.
But, as I said, I'm not sure that's correct.

That's it. I'm pretty sure that you've whacked the nail on the nnoggin there.

[Frelga]

Nope. Recessive genes is all it is.

Inbreeding is breeding between close relatives, whether plant or animal. If practiced repeatedly, it often leads to a reduction in genetic diversity, and the increased gene expression of negative recessive traits, resulting in inbreeding depression. This may result in inbred individuals exhibiting reduced health and fitness and lower levels of fertility.

In any case, if you are going to prohibit marriage for a certain reason, such as risk of passing on hereditary defects, you can single out only one group of population with higher risk.

[MithLuin]

Most of us carry rare recessive genes that will never show up, because, well, the chances of us making babies with someone else who has that rare, recessive gene is, well....rare I have heard estimates that we all have about 20 of these traits, but they are "buried" and will likely never show up to cause any harm. We might each have 20, but it's a different 20 for all of us

But...if you and your reproductive partner have a common ancestor, it is suddenly a lot more likely that you will both carry this same gene. And then you've got a one in four shot of having a kid with the problem.

The two classic illustrations of this point are hemophilia in the European royal families (most significantly, Russia) and the blue-skinned people of Troublesome Creek, KY. Both cases were due to a small, isolated gene pool in which people started marrying their cousins. Social ranks caused the isolation in the former case, while geography caused the isolation in the latter. Though having blue skin is not fatal - rather, it is treatable (hardly a reason not to have children).

Any population that becomes isolated in who they will choose to have families with will see an emergence of these traits. There are some genetic diseases that are extremely rare...except for in isolated populations, where they are common. Tay Sachs, for instance, tends to manifest in Eastern European Jews and Cajuns. It is standard practice for a couple from one of these groups (ie, the Jewish community of New York City) to get genetic testing done prior to marriage (or prior to starting a family). If both of them carry the gene, the couple may decide to adopt rather than to risk having a child with this devastating disease.

The problem with allowing a brother and sister to marry and have children is that there is no way of knowing what rare, recessive genes they carry. You can't test for it. Chances are, we'll name the resulting disease after your kid....


That's the medicine, anyway. As for society...

I see no problem with laws prohibiting marriage within close family relationships. A father should not be allowed to marry his own daughter if his wife dies/leaves him. Siblings should not be allowed to marry. I would certainly include first cousins in the ban, but I wouldn't go much further than that, because the laws should allow some room for unusual circumstances. But these laws are to protect the integrity of the family, not the gene pool. If a child is adopted, or if a parent is really a step-parent, the taboos should still hold. It is the relationships that are proscribed by law, not the genes.

Since the risk of lethal or debilitating genetic defect would never be 100%, you really can't use genetics to justify the law. Even in a case of two known carriers of Tay Sachs - they have a 75% chance of having a normal, healthy child. (Though 50% of that includes the child also being a carrier.)

[Jnyusa]

Tay Sachs, for instance, tends to manifest in Eastern European Jews and Cajuns.

It turned out that the Cajuns who were manifesting Tay Sachs had Ashkenazi ancestors. A very interesting case actually, from the sociological point of view.

Jn

[PrinceAlarming]

I think that nature would inanately find a way for us to not be sexual with our siblings...

But we also have close friends, and we say, "He/She's like by sibling..." And sometimes actually trying to achieve sexual pleasure from them feels like incest... (Just throwing that in there.)

I am wondering if there isn't a possibility that this is in some way a parallel to reactions to homosexual relationships: for many people there is an eww-factor in homosexual relationships, but probably everybody here would say that such a reaction is just a sign of a backward moral value system

I think that incest should illicit the type of gagging reaction it does. It makes sense to not want it.

Homosexuality doesn't spread genes at all... well, not naturally anyway. I had an interesting conversation once about homosexuality as an evolutionary reaction to over-population. Someone's reaction to homosexuality, I think, has more to do with a learned ideal. There have been many cultures that embraced homosexuality. And suddenly the Roman legions don't seem to get seen in quite the same light. I jest and digress...

It isn't just the value system that's the problem... Unless you count society as a system.

[Jnyusa]

I think that nature would inanately find a way for us to not be sexual with our siblings...

It seems that it has, Prince. When this topic came up on B77 I recalled the studies done in the Israeli kibbutz. Children who are reared together before they reach a certain age do not have sexual feelings for one another as adults.

I had an interesting conversation once about homosexuality as an evolutionary reaction to over-population.

I am inclined toward this view myself. Although we don't know the precise mechanism, there is some statistical evidence that female birthrates* rise following wars, in response to the wartime decline in population. (Population growth rates are governed by the number of females.) It would also seem that all people are potential bisexual, which leads me to believe that homosexualilty manifesting in the population in larger percentages might be a natural response to overpopulation.

Jn

* the percentage of persons born female

[Primula Baggins]

My kids' language immersion program throws the same group of 35 to 50 kids together from age six to age eighteen. Kids within the same year just do not date each other, though they're largely a close-knit, friendly group; "a bunch of cousins" is how my son once described it. But there are relationships between kids in different years.

I noticed the same thing on my coed dorm floor in college; couples didn't form there, it was too intimate. Couples that had formed elsewhere and then moved onto the floor together usually thrived, though.

Maybe the "TMI" reflex is a genetic defense mechanism. Maybe we tend to seek mystery in romance because that pulls us outside our familiar communities and cohorts.

[nerdanel]

It would also seem that all people are potential bisexual, which leads me to believe that homosexualilty manifesting in the population in larger percentages might be a natural response to overpopulation.

I'm having a hard time following this. In my case:
- One of the reasons that I find heterosexual sex strongly unappealing, is the possibility of conception, which just...illogically destroys any appeal that the "traditional sex act" might have.
- One of the reasons that I find homosexual sex strongly appealing is tha"the purpose of sex" is ipso facto not reproduction. It can only be an expression of the feelings (potentially, the love and commitment) between the participants.

Both of these feelings are just that. Feelings. They are instinctive. In some sense there is conscious thought underlying them, but they are at some level part of subconscious orientation, rather than conscious choice. In addition to these feelings, I also think:

- This world is severely overpopulated.
- I would not wish to contribute to that by reproducing.
- To the extent that I should use my skills to help to develop the next generation, I believe this would be better done by mentoring (someone else's) children, maybe adopting children in the very distant future, or at a meta-level, working to create policies and systems that favor these children's needs.

I think that it is these conscious thoughts and views, rather than homosexual orientation (or the feelings that in part underlie it), that are my response to overpopulation. And neither category of thoughts, frankly, seems particularly common among homosexuals. Most homosexuals I know are as hellbent on reproducing as most heterosexuals I know. And I have heard both lesbian and gay male couples express all too frequently that they regret that they cannot have a child "that is a product of their love." So I wish, Jn, that I thought that homosexuality was some sort of natural response to overpopulation ... if it was true, that would give us some role (and a very worthwhile one) in the "natural" scheme. But I do not understand how you can reconcile your idea with the large numbers of homosexuals who seek to have their own, biological children.

[vison]

I read recently that the Hemophilia in the descendants of Queen Victoria was due to a rare but not unknown spontaneous mutation: it had not existed in that bloodline before. The article I read said it was not due to cousins marrying.

Human beings reproduce sexually. That's why we have sex. But we are also humans, and like nearly everything else we do, it's just not that simple.

[Primula Baggins]

For an increase in homosexual orientation to be a product of population pressure requires a mechanism, and it can't be an intellectual one; it has to be biological. And the effect must somehow be produced before birth, in the next generation.

The only comparable thing I can think of is the shutdown of menstruation and thus fertility in starving women. But that's a simple feedback mechanism.

I have trouble believing statistics on the percentage of homosexuals in the general population through history. It may seem as if there are more homosexuals, but that could be and probably is a product of the fact that there are now places where one can be openly homosexual without losing one's job, friends and family, or life.

Through much of history, too, I wonder how relevant sexual orientation was to how people had to live their lives. A woman who was gay would probably still marry and have children; typically she had no choice. A man who was gay would probably hide it by marrying and having children—and in the poorer classes of society, it took the combined efforts of a man and a woman and older children to keep a family fed and sheltered. A single man would starve in a harsh climate. See the history of the Catholic church in Scandinavia, where priests were allowed to marry for hundreds of years because a man couldn't survive without a wife. And even after celibacy began to be enforced, in the Middle Ages, it was conventional for a priest to have a "housekeeper" by whom he would often have children.