In this exact circumstance I'm going to have to go with moral. The only reason why is because it is a scenario pertaining to two consenting adults practicing safe sex. There's no real health issue, no taking advantage of one party or another and no exploitation that I see. And my personal view on sex in general is that if it's between two consenting adults then it's not really any of my business.

An alternative thought exercise would be if two siblings were in love and wanted to be with each other. They decide to take permanent precautions and get both sets of tubes tied and decide that if they want kids they would opt for adoption. Societal norms aside, would this be a morally acceptable situation?

Far be it from me to judge what 2 consenting adults do.

So, if we're talking about completely consensual sex between adults, such as siblings and even parental and ADULT offspring, it's not immoral at all. I don't have a sister, but I once lost a giirlfriend to her brother and thought that must be the perfect love ... brotherly/sisterly love combined with passionate sexual love. I also knew two boys in high school who allegedly got their first sexual experiences from their sisters. I'm a Cyrenaic hedonist and believe that ANY relationship between ANY two or more consenting adults, for whatever purpose - sex, procreation, companionship ... whether or not an exchange of money or goods is a part of that contract, is their business and not mine, the law's, or anyone else's. Even the most vehemently conservative extremists of every religion are as subject to DNA's draw to pseudo-procreative acts as anyone else. You can't escape it and nobody has ever given me a good reason to want to escape it.

That guy sucked you in with a bullshit question. The god of Abraham, on more than one occasion created situations where incest was necessary for the human race to survive. I would turn the table and ask him to show anywhere that incest is promoted more than the "inspired word of god".

In most (virtually all) contexts, it's immoral because it's harmful. One (or sometimes both) parties are too young to give informed consent and/or there's a dysfunctional power balance in place.

I have no issue in theory with, say, two adult siblings shacking up of their own free will. Yes there are genetic risks with any offspring, but not nearly so much as is often supposed and less than some of the genetic risks we generally don't second-guess in more conventional relationships. Yes, I have grave reservations about crossing certain lines even in adulthood, and wonder what younger dysfunction was present to open minds to this sort of relationship. But in that limited circumstance I don't see a clear harm in not prohibiting it.

I cannot see a parent / child coupling ever being harmless, even with an adult child. There, we're back to the psychological power dynamic imbalance again. Clear interpersonal boundaries are essential. Some configurations just aren't defensible or rationalizable, ever.

Society has certain rules be you a religious or not. There are many religions, I'm sure that would welcome the practice of incest. I like to consider myself a liberal, live and let live, blah blah, but I also work in family law. The cases I have seen in 35 years with incest somehow end up to be more one-sided. Again, with the male convincing the female the it's ok. In fact look at all these people on this website that agree with me. I'm sorry but I disagree. If the only person you can find to form a loving sexual relationship with is in your immediate family, you might want to seek counseling.

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.

I don't like the question as written, either. Because, frankly, if we used the words unethical/ethical instead, it could be either. But the probability is so high that the privilege would be abused, I have to say that it's immoral about 99.99% of the time.

This question presupposes that a sexual relationship between consenting adults is always good, and is framed to minimize or remove most of the obvious problems with incestuous relations: power dynamics, possible genetic repercussions, etc. But incest is always a slippery slope, and not for genetic reasons as much as social reasons.

When people are related to each other, they already HAVE a familial relationship. Introducing sex into that relationship is likely to have significant negative consequences, and they cannot all be foreseen ahead of time. Woody Allen chose to become sexually involved with his then-wife's adopted daughter Soon Yi, who later became his wife. They weren't genetically related, and they are still married, but that relationship sundered his family, and ALL the other relationships in the family unit were affected. Woody's choice, to sexualize a relationship with a young woman who once thought of him as a father figure, is a selfish choice, and ignores the impact on the greater family constellation.

I know the post-writer tried to avoid the obvious father-daughter power discrepancy in my example, but the fact is, all relationships have power dynamics, and they can't be ignored. A pair of siblings shares a wider family together; will they brazenly display their affection for each other to their parents? and other siblings? or keep it a secret? Neither is a good choice.

No relationship happens in a vaccuum, and adding sex to a sibling relationship is almost always going to be the wrong thing to do.

Having said that, imagine two ageing siblings living together, whose parents and other siblings have died. Perhaps one of them is disabled, or crippled by poverty. They love each other, and always have. No one will be harmed if they decide to become lovers. But no one need know, either. Both moral, and ethical, standards upheld. This falls into the 00.01% of cases mentioned above.

If they're consenting. that means they are adults (because minors cannot, by definition, consent to sex). If that's the case and there's no possibility of offspring, I really don't care, personally. None of my business.

I think that the general aversion to incest goes back well before Christianity, so it's not just based on a religious taboo. It also seems to be very rare among most higher animals, certainly the primates, although there are exceptions, and sexual curiosity (I.e. exploratory, rather than penetrative sex) often occurs in animal family groups.
When a female animal comes into heat, and emits pheromones, it seems that generally other siblings in the group are not attracted by those pheromones, so there's a biological restriction against it.
One of the main human objections to it is that we generally have a different sort of relationship with close relatives to the sort of relationship that leads to a 'normal' sexual attraction.
That's why the cases where siblings have been raised apart and then happen to meet, not knowing that they are related, and fall in love and have sex, are so interesting, and so hard to condemn. It basically goes back to my point that the relationship you have with the person that you know is your brother or sister, and that you were raised with, is not the sort of relationship; that usually leads to sex.
But, with all the caveats and qualifications that have been mentioned by the poster and others (safe, consensual, adult, etc), then there's no a priori reason why it should be wrong.

How did Cain and Abel, the only two offspring of Adam and Eve, produce children? - Sex with their mother? Or if Adam and Eve did have other female children who are not mentioned, they would have been full sisters of Cain and Abel. Enuff said!

From what I've read, it's about keeping order in family and society. If sons can take mothers and sisters to bed, they would dethrone their fathers and brothers. Fathers would murder their sons. If daughters can have sex with their fathers, it would misplace mothers. Mothers would kill their daughters.

So, we now have extended rules that first cousins are not to have sex or marry each other. Same reason... families would end off killing themselves over affairs. In short, incest, or the possibility of incest, leads to murder in the family.

Instances where incest happens and it is accepted is in tribes. Males have children with many women. Women have children with many men. There are lap overs in parenthood as children born into the tribe are the tribe's children mainly under the care of their birth mother and her close siblings. Different system, so different rules.

Incest also happens in the animal kingdom. Animals don't have the intelligence of humans, so they may not get jealous or have a taboo thought of incest. I have heard of male lions killing off the offspring of previous males when they mate with a new female. I think that is more of a lineage dominance factor though. I've heard of dogs of the same litter mating with each other. They don't have the rules humans do.

I can’t ascribe a moral/amoral label to incest because it goes against our genetic programming to mate with close relatives. Therefore it isn’t a subject that’s “moral” or not, it’s a subject that’s beyond simple morality and into an area of being human.

I am going to say immoral because there is no such thing as 100% Safe Sex, they are still choosing to take the risk and have that slim and very rare chance of creating a child between them.

According to the Christian bible, it must be. ADAM and EVE only had two sons, Cane and Able. Able was killed by Cane.
According to logic Eve must have been pretty busy procreating with Cane and Adam. Wish I had an Eve in my life! ?

Morals are made up by people, so technically, it's considered to be immoral by society's standards. If we lived in a society that thought differently, then it would be moral. What I'm saying is that morality is subjective. I voted "moral" but really I'm saying it's neither.

Here's my non-scientific take on this: Incest is not immoral per se. I think there is a natural evolutionary taboo because of the biological disadvantages (mutations, abnormalities, weakened gene pool, etc.). Some other animals share this taboo.

However, I also think the taboo was commandeered early on by religion and declared immoral. It's another tool by which to control the masses.

There is no such thing as morality. It's only all about suicidal ethics and whatever state society happens to be in. Currently, I think, anything beyond a first cousin is allowed to be married in the US, so technically incest is legal between 2nd cousins etc. Back in the heyday of middle ages, you can only imagine what interesting relationship dynamics existed. Morality and immorality suppose the existence of a set of universal rules regarding behavior, and I think we all agree that's basically bullshit.

In this country, in this current social climate, I'd say immoral...some other place, another time?...who knows. There sure seemed to be a whole lot of it in the bible...

Immoral isn't the word I'd use, revolting is closer to it

when my mother was a teenager she fell in love with her own brother but didnt know he was her brother my grandmother had given him to her mother to look after as apparently in those days it was often done espcially if there were already another baby on the way . Charlie, the brother had come back to my granny as a teenager because the grandmother had died - No-one told my mother that Charlie was her brother until things started getting out of hand - I imagine family secrets like this one are hard for the family to contain and or deal with and that when the truth does come out its uncomfortable for everyone. I suppose safe sex isnt always safe as it sounds and isnt good for the family gene pool- I really don't think its a christian influence as most people would be concerned about the genetic defects from close alliances.

Personally I don't have anythingagainst the act of incest.. Quite frankly I find it to be none of my buisness what consenting adults do.. My only qualm against it is when offspring are produced..There are too many risk involved with the offspring from such a joining.. However as long as no kids get produced then I say fuck all the cousins and sisters n brothers ya want. Might not be my cup of tea and I don't understand it but who am I to judge.

In my early teens I had a friend who was having intercourse with his younger sister. It was a sex education class put on by her Gril Scout Troop leader that helped her understand what she was doing was not the norm, and she stopped it. So far as I can tell they both grew up to have normal productive lives, both were well educated. Interesting that she knew that I knew and has made it obvious she wants no contact with me, so there has to be some ongoing self concousness about it.

Well... I voted "moral", as long it is between consenting individuals that are not in relation of legal guardianship/parent-child or other implying position of authority of one participant over the other.

• first - sexual act as such has no moral implications of any kind to me - I see it as a physical activity no different than eating, breathing, drinking, etc;
• second - the choice of a sexual partner is a matter lying purely in the personal domain of the individual. If something is immoral here this is the effort of third parties to meddle this deep in other people's personal affairs.
• third - as long as consent is present and the participants are not in any relationship of authority (parent-child for example) I would ommit the "adult" requirement based on the facts that: most such activities take place between consenting minors, without observable negative consequences (there are easily definable reasons for this); the legal definition of "minor" covers the period of puberty which is normally the most intense part of an individual's life in regard to sexual desires, due to the hormonal storms raging through one's body in this period;
  All of the above based on the strict assumption of a freewill consent - any form of violence, coercion, manipulation or other way to involve a person (regardless of age) in (not only) incestous sexual activity against their free will automatically should render the act utomatically both immoral and illegal.

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 ?