I don't know how many GREATS to add, so I will just say, ask my grandma Eve...since for a generation or so every male on earth was committing incest with her...and there are still lots of people buy that shit, without thinking about it...BUT on the serious side...I am in total awe and respect of all the professional postings...I can almost understand how everyone has an opinion, but only a few have actual experience....BUT KNOW ALL THE ANSWERS.... based on religious teachings....I have never experienced it, but an good friends with a man who grew up having sex with his year older sister, they are both married to others, but he is the father of his sisters 3 children, since the hubby is sterile ! ALL ARE HEALTHY, HAPPY, AND LIVING GOOD LIVES. So to that extent, I would have to say, it's all none of my business, and so long as they are no in jail, what the hell..as I said, I have never experienced it, but did have a sister who was my BFF before she died.

One does not have to be religious to believe in the laws of nature and since "safe sex" is not only a myth but man-made option than I rule that out as a test and say the consequences for incest are evident by the "fruit" being produced by those that choose it.

Taking procreation out of it, what consenting adults do to amuse themselves sexually is none of anyone else's business.

Morality or immorality is a human question and as such, incest per se is not immoral, but society has decreed (with some good reasons) it to be immoral. I am a product of my society.

It's like anything else: if society deems it acceptable, it is. But if it's not acceptable, when it happens, even if consensual, it can cause severe traumatic and psychological distress, especially because it is a highly sensitive issue.

Ewwe wwww

Wealthy and powerful families used to intermarry with their own family members . This often led to health problems for the children they produced , Is it moral to intentionally and with forethought create geniticly sick children ?

Even if you were to remove the procreation from the equation, it's still a question of health, but rather than sexual health, it becomes one of mental health.

Remove the word "moral" from your question and ask yourself what is the evolutionary mechanisms that allows this to happen and also creates a social taboo. The urge to procreate is the most fundamental of all living instincts, but there are also a whole host of other instincts that curb that urge which are designed for us to pick the best mating partner to pass on our genes. Our evolutionary minds have been designed to reject familial relations at adolescence, unless there are no other options, because the first directive of reproduction supercedes.

History is rife of examples of incestual sibling relationships, and most of them show signs of some forms of mental and social dysfunction.

Mostly this has to do with power balance in a relationship. Obviously, mileage may vary depending on the two people in question. In order for it to be consensual, both parties have to be of proper age, but that's just where the consent discussion starts. There could be a lot of other things going on. Perhaps one is manipulating the other, maybe one is older, or can use guilt over a family situation, or one is struggling and the other has resources to spare. Even if there were nothing biologically wrong with the situation, there are way too many things that could cause an imbalance of power, which is the root of virtually all abuse cases.

Just because one does not believe in a God does not mean one can be a sexual anarchist.

Biologically everybody wants to experience the pleasure of sex as soon as they find their "tickle zone". Babies get erections and rub their pelvis on toys, but that doesn't mean you poke them with a vibrator! Even animals wait until their young are of age! Incest, whether of age or under, is only practiced in the animal kingdom when the herd is too small, or other options are limited.
And this brings me to instant gratification versus waiting for the right time. It's easy to form a bond with a sibling in this day and age of multimedia and staying home for safety. More time home equates to Idle Hands (devil's playground). Instead of waiting for somebody right, you use each other for pure gratification. Later on, she'll get married, or he'll find "the one", and that sibling bond will be missing because you cannot look each other in the eyes, out of shame of yourself, not the other.
There are many types of "love". The love for your mother is not the love you feel for your pet. The love of ice-cream cannot be mistaken for the love of your life. Sibling love should not be sexual love, morally, logically and pretty much biologically.

Well...if you are looking at it from the biological perspective of reproduction, there is that risk of passing on genetically inherited flaws and afflictions (weak chins, poor vision, disabilities) so it may not be wise. On the other hand, if you don't have any genetic markers for health concerns you would strengthen your bloodline and could lead to a better, faster, stronger (depending on strengths) specimen. Kinda hard to get past the 'eww ick' factor. When you are your own aunt, things get weird. But you probably will get something better than socks and an autoharp cd for your birthday. I don't think that immoral or moral are really the best choices because morality generally is passed down through religious dogma. Better to say gross or not gross. Not easy to get out of the gross camp. If it were a social norm with which I had grown up I would likely feel differently.

Uh- do I really have to answer that? If you think about screwing your mother, father, daughter, son, brother, sister, etc. instead of the big pool of humans you have to choose from, then I'd suggest a shrink. And I don't need to hear about the flawed theory of cultural relativism. It's proven that incest, and therefore, the overlapping of genes, causes serious physical and mental problems.

First, a Christian has no way to oppose incest because it is practiced quite a bit in their religion. Second, it might not be moral or immoral. Third, in the vast majority of cases I guess it would be immoral because of the family dynamics involved. Fourth, consider the strongest case of sibling incest that might be not immoral, two people who do not know each other at all and never find out they are siblings. In that case, I don't know. Fifth, safe sex doesn't mean no pregnancies. It is difficult to not have revulsion for the idea.

Ironically, in the Biblical worldview, incest is not only acceptable but is the very way in which our species has survived - twice. Adam and Eve, then Noah and his happy little family. Disregard the fact that such a situation is biologically impossible. Anyway, back to the real world.

Incest itself is neither moral nor immoral. It would be immoral for children to come from such a relationship, because inbred children have a very high chance of being born with a genetic disorder. However, incest itself is no more moral nor immoral than gay, lesbian, anal, oral sex or all the other kinky categories one can find on Pornhub.

Taboo & Both.

It's commonly not consensual and, therefore, immoral.

It's also common that separated siblings find each other. If you don't honestly know, how could anyone claim it to be immoral.

Immoral if there's a kid because then he/she is screwed for life. Moral if they are consenting adults with no consequence.

It is immoral, because it messes up the best family dynamics. Imagine a wife or sibling think they did not get treated properly in a family setting.

An adult engaging in sex with his/her offspring is wrong, we all know the psychological effect of pedophilia and the high risk of genetic mutation.

So far 7 people are super creepy.

What is morality? If you commit it and don't know, then most people today would say, ugh, so what. The ancient Greeks, Oedipus, would punish you. It is a man made construct and not good scientifically for reproduction of the species. AND, personally, i would gag to do it. But if it isn't rape in any form, I'll keep my mouth shut.

Morality is a man made construct. It doesn't exist on its own. Incest is present in animals and I'm guessing in pre-historic societies too. But they also had other bad practices too like rape, pedophilia, etc.
In a just society, where no one is exploited, where there is no age or power imbalance, such an act will not be unethical or immoral like you said.

God populated the world through incest, ok with him. Makes me feel nauseated, inner moral code says no to incest.

With morality being the simple distinction between right and wrong, good or bad, then the very basis for the taboo of incest, that being, that over the history of humanity, it generally caused harmful results. Are there exceptions? Certainly. Again, experience finds the exceptions few and far between. What I find more immoral is the lack of education on sex in general, which I blame mostly on religion.

IF there is some love and caring involved and the couple involved practise safe sex...let them have at it.

I think this issue needs a more reflective approach. Think who people breed with. Humans breed with humans. More often than not people breed within their own ethnic group. I hate to employ the term race but most people produce offspring within groups their are familiar with. Despite increased mobility this remains a fact. Just look around and see how many people have partner that they share many traits with. So it might offended your mindset but arguably it is not as unnatural as many people make it out to be.
The issue of degeneration due to genetic mutations is a totally different issue.
As much as I appreciate people passionate responses they are extremely biased.
I wonder whether their are pet owners or farmers among the respondents here who feel attracted to specific breeds, or shall I call them inbreeds?