From a biological and evolutionary point of view, sex among close relatives is not advantageous because of the possibility of decreasing genetic diversity and increasing the chances of offspring having genetic disabilities (being homozygous for bad genes.) Boys and men normally have an instinct not to be sexually attracted to sisters if they were raised together.

More taboo than moral/immoral (a false dichotomy). The taboo, according to various sociologists to whom I've spoken, is more about extending social links and familial networks than avoiding genetic disorders. Human beings survive because they form societies, a lone human is mere fresh meat to most of the world. Extending links through marriage in those societies has always been vital to our survival as a species.

I caught a friend of mine in Texas in the shower with his sister (both adults). He later just smiled and said "Incest is Best", all I could do was laugh and forget it. They were certainly enjoying themselves, I'll say that.

The "Game of Thrones" scenario in which adult siblings who are more or less peers mutually desire one another sexually to enough of a degree that they overcome the social taboo and consummate their mutual desire is vanishingly rare in real life. If you came to me with that scenario, I'd probably say, "Sure, that's taboo, but it's not immoral."

But that's not most incest. Most incest is a (usually male) family figure with a lot of power using that power to sexually exploit a younger, relatively powerless child (who may be of any gender). And it does lasting, severe damage to that child's psychology. The damage may manifest in different ways as the child ages, but it's never good and it takes a LOT of time and a LOT of painful effort to overcome.

So, that's why I voted "immoral." We're not just talking about a social taboo. We're talking about rape, up to and including parents raping their children. Very immoral, because very harmful.

A very difficult question - my instinct says immoral but my brain says moral. I think it would have been interesting to ask the theist his opinion on Lot and his daughters though!

The whole question revolves around any harm being done. If the two people are adult and it is fully consensual and there are no health consequences then two people are having enjoyment and no harm is done to others. It is immoral to deny two people enjoyment if there is no harm to any other person.

To each their own really but I personally find it gross because it was bad enough having to hold my sister's hand after a quarrel, let alone touching each others nasties or cousin's for that matter..

Safe sex is safe most of the time.

Not having a sister, and all of my cousins being happily married, it's not a realistic issue for me.

Just look at some of the royal families. It seems to me like a broad gene pool's advantages outclass breaking the taboos on family relations.

Life is a sexually transmitted disease that is inevitably fatal.

Biologically stupid, and the quickest way to ensure future generations are subject to bad mutations.

If you were in an adult consensual sexual relationship with your sibling, would you be able to tell your best friend? Your parents? Talk about it with the girls over cocktails? Laugh about the queef you let loose after getting pounded all night by your BROTHER?! Man, I don't know about morals but I do know if you hide or lie about things, it's usually because you know it's not right.
I don't have brothers but have thought "if I had a brother and he was a hottie, would I ever find myself sexualizing him?" I can be a bit of a floozy! But I'm pretty sure I wouldn't be able to introduce him as my new boyfriend at the office party. "Oh, tell us all how you met!"
"Mom brought him home from the hospital when I was 2."

it is moral because it is between two consenting adults. otherwise you could ask the same question in the context of same-gender sex. it all depends on the dogma and societal do's and don'ts of your culture... some say it's immoral for two men or women to have sex. awkward, but not inherently right or wrong IMO...

I voted immoral because of the genetic concerns in future generations. I qualify this however by saying that safe sex practices and a "healthy psychological relationship" (if that's possible) would have to be used. This is something that I feel isn't practiced in most incestual relationships therefore incest in the practical sense is immoral.

Because it's gross to bone your sister, it's your sister, like you shouldn't view your own family as boneage material.

I think our society has deemed it immoral. But, personally I would think if each was of the age of consent and were not trying to have children, I see no logical reason to claim it's immoral. I think under those strict circumstances it's amoral at best. I'm sure that's not a popular view. But if it offends you, ask yourself why and if it's solely because how you were raised and/or the societal mores within which you grew up.

I think you have a moral obligation not to risk birth defects. Inbreeding is the leading cause of it. We've known this since the Egyptians.

How is this even a fucking question? NO it is not okay to fuck your kids!!! We don't need an invisible man to have a moral code.

Logically the only thing wrong with incest is it leading to children that would suffer for it, however, I would like to point that there is a lot of cancer in my family and I am perfectly legally allowed to have children with a man that also has a lot of cancer in his family.
I could be told by a doctor that there is a 99% chance if I have children that they will get cancer and yet I can still do that without anyone thinking ill of me for it.
People with mental disorders have kids with other people with mental disorders.
Small People that know they are going to have Small children. (I hope that's the non-offences term for them)
Or any number of other problems.
If you say you can't have kids because they may have problems with their health where exactly do you draw the line?

it's not healthy or natural in the animal kingdom mostly and I agree with nature. on a personal note, it just seems wrong.even like my brother's ex-partner seems wrong

Typically this involves a child. That’s the reason for the taboo. It’s psychologically damaging to a child. As for cousins, it’s their affair.

Morality is a construct of cultural ideology, sociology, and religious conditioning. QE2 married her cousin and family intermarriage was abundant in many cultures. Morality is a reflection of how we've been taught some actions are ethically wrong and a flaw in character. As a humanist, if consent isn't violated and no one is hurt, I couldn't care less what the wizard behind the curtain thinks.

Stepping away from religion is easy for me but I am not an atheist. Please remember that my comment is strictly opinion based. On the subject of incest, I consider it immoral, there are so many people out there in the world for someone to find a mate. The fact that a family has a bond that we all respect and understand is something to take into account. Say a brother and sister commence in the sexual act together and become pregnant. should the abort the child because society will judge them, are they taking into account the possible problems that the child is going to grow up with? ie: my daddy uncle is sick and my aunty momma is mad cause family won't help them.

I love my family but to lay with them in the act of love is something that pulls into question one's sanity and the clarity of the situation when presented to them. personally, I could not do it because I am not attracted to my sisters that way.

Ultimately grey. Not a participant personally, but who is to challenge another if there are true feelings.

thats why there is health issues.We found a work around called contraception so its all good to sleep with mummy,hell why stop there we have the whole animal kingdom lets start doing them aswell.No contraception gives a 100% guarantee so its wrong.Just because we can does not mean we should.Muslims practice incest first cousins but it has been proven many of them ignore the rules and have to hide away or evan kill the end product..I don't think wild animals practice incest its probably just a human thing.we need to live by some standards i think,first comment so go easy on me guys and gals and all the other sexes out there

I think it's more of an issue of how it might affect the dynamics of your family WHEN discovered. Also, it's kind of like when people date at work, break up, and how it affects not only their work but their co-workers sometimes. Just not a very wise relationship move. Moral vs Immoral - that's a tougher call. I guess there are personal morals and community morals - and sometimes it's not easy to separate the two, unless you live in an isolated situation. Rarely a wise choice - I'd say, and frowned upon by most, for sure - I'd just steer clear. I'm sure there are exceptions (I sometimes wondered about Angelina Jolie and her brother). We all might say "who am I to judge" - and then we do, we do judge. So, again, not a winning move.

It is immoral as long as either one is not an adult with the intellectual ability and knowledge to understand their actions. They must not have had psychological or physical incestuous relations in their youth with each other or others. There should not be any history of incest or pedophile relation with any other adult prior to their relations. I do not believe they should be sibling or parent child relations. If they have incestuous feelings that are troubling they should seek counseling.