No, there is no genetic diversity issue.

The only time you have a genetic diversity issue is when you have a small population who only breeds with a small population over 3 generations. Such as this one village in Syria which has been cut off from the rest of the country for the past 60 years.

Genetic diversity issues are a blanket-term that covers a multitide of issues. One of which is when a family in-breeds over a course of time, or small populace breeds over a much longer course of time, and no new genetic material is introduced. The chances of this happening at this stage in history with a small populace is fairly low given the human trait to migrate. Incest would be more a threat if allowed to occur large-scale.

Laws were established preventing incest through a great deal of the world at some point or another, for many reasons. The only truly valid ones are that close siblings breeding significaly increases the chance of genetic abnormality (note: out of four children, these two have a son with epilepsy and a "learning difficulty" and another child with "special needs"), and if allowed over time creates issues with genetic diversity fading.

From a scientific point of view, it is wise to prohibit people from taking steps towards the degredation of our race. I'm sure there are several moral reasons as well, but I couldn't care less about them.

Set your 'ewww' reflexes aside for a moment and follow with me.

If it weren't for genetics and taboos, siblings would logically be high up on our 'likely partners' lists.

- We already know them.
- They're there.
- We probably have a lot more in common with them than with non-siblings.
- We already share some kind of emotional tie.

In other words it's likely a case of 'if we let one couple do it, everyone's going to do it', which -would- be bad for genetic diversity.

Hence the very strong societal taboo on it.

If two people are totally healthy then there's no reason to say that their children will be deformed because of inbreeding. That said, two related people are obviously more likely to share faults in their genetic makeup or environmental diseases.

Still, incest laws are based more on distaste than out of concern for possible birth defects, as evidenced by the lack of law banning many other forms of coupling that carry an increased risk to the child.

To be perfectly frank, in an era of contraception.. incest is not such an issue.. but to anyone (heterosexual) with a sibling of the opposite sex, it's a really really unpleasant idea. Which is one of the reasons I find it entertaining.

As an aside, I think Viscanti should be able to marry close family members in game.

It's pretty abhorrent to me also, I could never have sex with one of my brothers. I know I feel that way because of my socialization though.

Yeah, how dare you! Incest is perfectly fine, but gay marriage isn't!

Not really, and for quite a few reasons.

The most important one being "Nobody to split the wedding bill with."

But seriously, all those things you mentioned are the exact reason why its not very likely.

Looking at thier children as having problems isn't really significant. Firstly, most students these days have "learning difficulties" and as far as I remember, neither epilepsy or learning difficulties are diseases which are more prone in interbreeding.

What the hell are you talking about?

I reject both of them, but if you are going to allow one, there is no reason not to allow the other.

Er, no? Incest makes it more likely for someone's recessive, unpleasant alleles to meet their corresponding genes. Which is why making it illegal for incestuous couples to reproduce equals a form of eugenics.

And yes I was fully aware of that note about incest. I just like pointing out Lot's story because, well, it's fun.

Ack. I didn't mean to imply that gay men wouldn't be disgusted by incest.

Then point out the whole story.

Like the fact that he is criticized for going to Sodom, and is only saved because he is Abraham's nephew, or the fact that the Children of Lot end up being the big bad guys, who later are not only denied the ability to ever convert or be part of the children of Israel, but also attempt to both Curse, and later seduce the Israelites as they come out of Egypt. While the story of Lot is indeed interesting and fun, its also a clear example of "What not to do." But in the end of course, through a loophole a woman is allowed to convert and becomes the Grandmother of King David. The parallels between Lot and Noach are also very interesting to compare, where Noach's sons get him drunk and sleep with him also, to start the world over again. Although some do praise the daughters of Lot because they assume that they assumed, that after the destruction of Sodom, and the death of their mother, they were the only 3 people left in existence. But I am sure you knew all of that also.

I was saying that incest was not the only form of Eugenics. I also highly doubt that people were even able to associate the harmful affects of Incest with the act itself, considering it is something that was always done amongst families who had honors or wealth to keep.

Many other and less subtle forms of eugenics would be such things like rights of passage, which would require a person to fend for themselves in the wild before having children of their own. Or restricting certain classes from only marrying within that class.

No the reason why incest is taboo in most cultures, is because of the psychological ties between people and relationships, and wanting to keep people from confusing the emotions they have for their family, with the relationships they would later have with their spouses, which are entirely different relationships.

I don't think this is true. I read the article yesterday, but didn't it describe two of their children with special needs, at least one due to genetic defects? It seems like it's possible on even that kind of scale since they're full siblings.

On top of that, I think Korben is missing the real reason WHY siblings are unattractive: it's a biological response to growing up with someone precisely in order to prevent this sort of thing. The same kind of thing has been evidenced in other settings (completely unrelated kids growing up in - I think - Israeli communes found zero attraction to each other because they'd always grown up in close proximity), and these two kids were seperated from a very early age and only met again when they were much older.

Genetic defects don't just manifest randomly, there had to be underlying faults in the parents or some sort of environmental factor that mutated and effected the kid's DNA. Which is what I was saying...I think, unless I worded it badly. I've been doing that a lot.

Untrue. I'm assuming you understand the basics of heredity - that is, dominant and subdominant traits. If parent a has allels Ff for some disease "F" and the other parent has FF, each child has a 50% chance of being an Ff themself. Now, if these children have kids with eachother, thats a 25% chance that they have the disease itself (both of them being Ff), making it a 12.5% chance in total.
Now, how does this apply? For each genetic disease that you don't have that is inherited in a basic way like this (I'm sure this extends to complex traits that I dont know about, but I dont know how), you can't be sure if you have a DD or Dd. So if either partner have Dd, and their kids have kids, they will have a 12.5% chance to have any particularly geneticly inherited disease, per kid. Now as there are many diseases and such, that means they are likely to have one.
By having kids with someone completely unreleated, you lower the chances of sharing Dd traits. If a DD and a Dd have kids, they *can't* have a dd kid.
I don't know if I epxlained it well, but thats the issues behind it regarding genetics. I won't take a stand on the issue, personally.

Exactly right, Dyr. Every recessive gene in either one of the siblings' parents has a 1 in 8 chance of occuring twice in the siblings' offspring and thus being expressed. People have a lot of recessive genes, and a fair number of them are harmful. So it doesn't take generations for incest to be bad; it can happen immediately.

Also, note that societal taboos come from real environmental or evolutionary considerations - we don't just form societies and make up random taboos. In this case, the taboo against incest is one of the few essentially culturally universal taboos there is. The reason, we suppose, is that people who found incest reasonable had offspring who were less fit than people who avoided incest, and therefore the "incest avoiding gene" became the norm - reinforced later by societal and religious taboos. Now of course, our genes don't know about the recently developed access to reliable contraception and so keep telling us EWWW about incest.

Interestingly, incest avoidance is good evidence against one claim made in the Question the Christian thread, namely the claim that morality would not exist in the absence of a higher power. Morality (at least some aspects of it) can evolve, just like the rest of our complicated behavior. I recommend the writings of Robert Wright and Richard Dawkins (though don't take this to mean that I endorse "The God Delusion"; I haven't read it.)

Hang on a minute: while I fully agree that morality can (and does) exist in the absence of a higher power, I'm not following why this is an example of that. Reacting badly to the idea of incest is a natural trait for most people to have, but given the existence said birth control I'm not sure that you can say intolerance of it is a "moral" thing. I'm still undecided on whether preventing incestual couples from having children is a moral thing or not, actually.

I didn't miss it, I just focused on the social failsafe since we have some measure of control over that one. The biological failsafe is there whether we want it or not. The biological one is probably not 100% effective, so the social one exists to cover the gaps. Together they achieve near 100% effectiveness.



Morality starts out as rules for behavior that will be beneficial to your group (usually the tribe). Internal conflict and competitiveness need to be harnessed productively instead of destructively. However, the tribe usually develops some form of religion very early on as well, so from my layman's POV it's hard to tell which comes first.

Well, probably if we consider the incest laws to be due to bad results in the offspring we should start banning people with diseases like AIDS to have kids unless you're 100% sure the kid won't be infected as well, and even then accepting that having a very sick mother isn't probably good for the kid, and also people with genetic defects that are dominant, and also people with genetic defects in general marrying to each other. Oh, and people adicted to drugs that can make their offspring addicted from birth (heroin for example). I don't see any law demanding a genetic analysis on parents who want to have kids so I don't think "think of the offspring" is a valid argument to keep it unless you're willing to admit diferential treatment.

Now, I am totally against this couple having children due to the problems that can arise and I find it highly irresponsable (I have the same opinion about a lot of people and groups of people some of wich I've mentioned before) and I would think adoption being a wiser option. But I don't think it's a law who should say who do they sleep with and I sure won't go telling them what to do.

I don't care about the religious arguments because Europe is mainly governed by laws and not by religious rules and governments. It has taken centuries of fight to get that and I hope it stays that way, and the different religions only worries about the spiritual health of the people that choose to folllow them. They would provide a better service then probably with a more limited number of people to control.