We find it gross because we have evolved that sentiment to prevent chromosome damage. Same reason we feel sick when we smell rotten meat. Our instincts are telling us it's not good for us.

I don't think it's a moral issue and I don't care if cousins or siblings do it as long as they are safe. Same reason I don't care whether people drink or do drugs, unless they are pregnant. What you do with your life is nobody's business but yours; as long as you don't hurt people, kids included.

you forgot "neither". not every action in the world is one or the other, some are not a question of morality.

is it moral or immoral to tie your left shoe first?

I do not view it as an issue of morality. As at least one comment pointed out, it's an evolved trait that makes us feel that way about it. it is not an issue of "morality", it's an issue of internal mechanisms that make us feel squeamish about it. and the reason that evolved should be plain to see in any heavily inbred community.

Medically speaking I first ask; How actually safe is "safe sex" considering that almost EVERY form of contraception is, at the very best, only about 80-90% effective, except, of course, for total abstinence or surgical techniques such as; 1) a irreversible Vasectomy for males and a total hysterectomy for females, or, 2) castration of males.
Genetically speaking, incest is a very hazardous activity in any human relationship between brother and sister, father and daughter, mother and son or first cousin to first cousin with a direct genetic link.
That is why, in the wild , most mammals and many other species will drive out their young once they are old enough to survive on their own to limit the chances of the genetic pool becoming tainted by incestuous in-breeding thus causing deformities ranging from very minor ones right through to the most horrific.
DNA strands, which every living thing are made from, are very delicate and very easily 'damaged' ergo Incest is NOT a religious Morality Issue but an Ethical and Genetic Issue for a living things and, on a personal point of opinion here, I think that with all the advancements in Invitro Fertilisation and random donations of sperm, etc, human kind is slow but inexorably heading down the road to a destination where in-breeding and the genetic disasters will become the norm unfortunately.

Ok, so we're assuming consensual sex, obviously. Between adults. Like, all parties involved are adults, not most of them.

Even if the potential for reproduction is involved, the potential for irreperable damage to the species is negligable, right? With such a diverse gene pool, regardless of how screwed up some subsection of the population gets through inbreeding (see Blue People living in West Virginia mountains...), there is a larger genetic base to mitigate whatever irregularities arise from the inbreeding of various small groups. As long as everybody isn't doing it, right? Although perhaps that's where the whole biblical provision came from in the first place. Too many villages full of people with hip-displasia and the cognitive inability to do much of anything other than fuck their siblings.

I mean, they inbred the hell out of dogs. You like your dog, right!? It might be a fantastic idea to selectively inbreed people. Just remove the ones with non-desreable traits from the gene pool. Although I'm pretty sure any sort of selective breed in humans is considered Eugenics, and that's generally frowned upon these days... Nazis fucked it up for everybody.

So, if you remove procreation from the picture completely (as the OP did)... then sure, why not? What about this consideration: what will children who grow up in an environment where Mommy and Daddy are Brother & Sister going to develop as their paradigm for romantic relationships? Since its obviously acceptable to fuck your brother or sister in this environment ("Mom and Dad are such hypocrites! Grandma says they've been hooking up since they were OUR age, but they won't let us do it yet..." ) what's to stop the kids from banging?

Assuming they are of the same age & maturity level, is this any more immoral than the parents banging? They would probably think its normal... enough... Keep in mind that aforementioned kids are probably not genetically related (unless adopted from same parents) as they cannot have come from original Brother & Sister, since we have already ruled out the potential for procreation in this example.

Synopsis: A moral acceptance of incest would lead to incest to become socially acceptable and potentially integrated into mainstream culture... but as long as there is no potential for children to arise from the union, it is no more or less morally acceptable than banging someone who isn't related to you.

In other words, if we ever find out the world is going to end in less time than it takes to gestate full-term, it becomes perfectly acceptable to fuck your sister.

P.S.- I am an only child.

Because as long as it's consensual and safe, no harm is being done.

Sex is never safe, when brounderies are not respected! Hearing stories from my peers as an older person...it does not bode well in old age! It appears to eat away at their mental health!

If you want to lower the bar to just propagation of the species.... Inbreeding is not good for the long-term viability of the species. There are a host of issues that can result.

WTF??

Any time close relatives have sex and a pregnancy results, the couple is playing sexual Russian roulette. Recessive genes that can produce disorders exist in almost every person, having accumulated over thousands of years. When close relatives interbreed, the risk of those recessive genes being in both parents and making a disordered child skyrockets. A disordered child is wasted reproductive potential. It is always better for people to find mates outside the family.

As long as they're two consenting adults it shouldn't be a problem.

Morality is societal relative. Morality exists before religion, and religion justifies it. Not the other way around. As the social mores changes as does morality and religious reason behind it.

It's so clear it's wrong, can't think of anything decent about it. We cannot do just anything we want. Sad if anyone thinks it's okay.

When playing around with sex, one may become pair bonded. As a teenager, I did with my steady girlfriend. She moved far away with her family. It was devastating for us.

Now think about the issues when one sibling pair bonds and the other does not. You are living with the tension of unrequited romantic love, with someone you will have a familial relationship with for life. This kind of mismatch will really test your patience or your relationship. So sex play with sibling without having a solid bond is hazardous, if not immoral.

On the other hand, consider a couple that falls in love and plans to delay pregnancy. Or siblings / cousins that fall in love and will have (frequent) "safe" sex. Of course, a single contraceptive is around 80% effective annually. (Always using two might be 96%. That means your odds of pregnancy are about 50% in nine years.)

If the children have 25% odds of having one (or more) active recessive diseases, the relationship is far less important than the suffering non-health of their progeny. So I conditionally call this reproduction immoral.

You don't want the tragedy of a cemented pair bond with someone who is likely to produce a diseased child.

So my advice to young people is to get your genetic testing as soon as you can afford to. Compare your test results before getting all hot and heavy. This is essential for siblings and cousins.

Incestuous relationships are more.common in certain areas of the world. We can't simply say "ew gross" because of our adversion to it. Genetically speaking everyone has offered why it's not a good idea as recrssive genes. However socially speakjbg there is no good reason why it is Immoral

It is immoral because it will lead to children with genetic deformitys

Ruins the sister-brother relationship, one that is based on traditional values excluding religious beliefs.

I don't think there is anything unethical about it as long precautions not to have children are done. I think to have children with a relative is extremely selfish and unethical due to the high genetic problems risks. I really think that anyone who is in a incestual relationship should commit to being willing to have an abortion if that situation arises. Of course there are other measures to prevent childbirth , but if they don't work an abortion should be had.

There's no morality about it. Its just fucked up. It has so many genetic and medical downsides that I would never condone it. But i think 2 consenting adults should be able to do what ever they want as long as it doesnt harm others

There's no morality about it. Its just fucked up. It has so many genetic and medical downsides that I would never condone it. But i think 2 consenting adults should be able to do what ever they want as long as it doesnt harm others

I know in many old cultures it was actually quite common, but due to the health issues it usually lead to collapsing dynasties.

It may be that we have several questions that apply and are being confused.

1. Is it a good idea for the individuals?, for example, when (if?) they move on to new partners they “divorce” . Will they have problems adjusting? They will have little if the support available to married couples.
2. Is it legal? Cultures wind up on many sides of this one.
3. Is it a good idea for society? Will it lead to clans, as happened in rural WV for instance?
4. Is it a good thing for the family? I would put in the slippery slope (gateway to father-daughter sex) in this item.
5. If they do have children who continue the “tradition” genetic defects will pop up.

Which of these apply to a definition of “moral”? And there may be many others.

There is a cultural taboo against incest not a religious taboo although in the bible belt of the USA marriage between first cousins seems to be common. The set up of most social animals makes incest uncommon. eg male hyenas will move to another group to mate. Some bird species eg swans mate for life so incest is unlikely.

Morality is a subjective term dependent upon the predominate views of the society or group within which the action is being judged. In my group of one, it is moral. If my group were larger I might have to change my answer, but I would have to know the disposition of the group. I might add that it would need to be a unanimous answer amongst the group.

Does it cause suffering? If it does not then its moral. Might be hard to explain to the neighbors but if its consensual sex between adults and there won't be any dodgy offspring then why not?

I was a psychiatric RN for over 30 years and abuse of women and children was my main area of expertise but I have to recuse myself in part. If not sn act of aggression, and consensual that can be different although I might have difficulty endorsing it. I would have gone to bed with my cousin in a minute although we haven’t been in touch. Never my sibs and by the way I’m not a Christian... however I might hop on to bed with you as you are very attractive and sexy