I think an incestuous relationship would only be a breach of trust, responsibility, etc only if it wasn't consensual. As would be any relationship that wasn't consensual. I agree it could be reproductively damaging but there is plenty today where this can be avoided. As far as being psychologically predisposed to avoid because we're biologically driven to broaden our gene pool, how exactly does a homosexual relationship broaden the gene pool? Shouldn't we be psychologically predisposed to avoid those as well?
Gay relationships don't produce offspring. There's no need to think in procreational terms in such circumstances. If a man who is attracted to men has sex with a man, he doesn't need to think about looking for a mate outside his own gene pool to further his lineage in a way that benefits the immune system of the child, though, even in homosexual relationships, it is extremely rare to find incestuous ones, more so even than incestuous heterosexual relationships. This is probably for the same reasons; we're predisposed to look for mates outside our immediate families.
I agree homosexual relations have been prevalent throughout the years... I know as far as ancient times. But during these times when homosexuality was also very prevalent and recorded, there are plenty of examples of incest as well. Mostly during the Roman times and I know Cleopatra married her half brother. I think even Edgar Allan Poe married his cousin... In greek mythology, incest plays a major part in plenty of greek myths so it's obviously something people thought about even back then. In greek myths, incest is never treated as wrong or distasteful from what I can remember aside from the story of Oedipus. Even in the bible, whether people believe it's true, incest pops up plenty of times. Actually in the bible, there are plenty more mentions of incest and actual incestuous relations than homosexual anything. And this is AFTER it's declared as not ok in the bible. I think the only reason consensual incest relations are rare is because there is a very small pool to pick from. Where as anyone else has everyone else in the world who is not related to them to pick from.
There isn't really a small pool to pick from. Every person with a blood relative (everyone on Earth) has an opportunity for incest, yet it is exceptionally rare to find instances of it. Most instances are men raping young girls or boys, and very few are consensual incestuous adult relationships.
Also... homosexuality occurs naturally across various species... actually it doesn't because nothing aside from humans living today belong to the genus "homo"... But yeah same sex relations, I get what you mean
Animals do all sorts of weird things so I hardly see them as a way to validate what is natural or supposed to be.
So do humans; fashion (wearing fabric or animal skin clothes to attract mates or look pretty/handsome), war (killing our own kind in vast numbers), shaving (removing what little warmth keeping hair we have, usually for sexual attraction purposes), subjugation of other races, drug use, destruction of our natural habitats, resource depletion, religion, suicide, thrill seeking, and of course the wierdest of them all; money and money systems.
And I've seen way more frequent incestuous relations in animals than I have seen examples of same sex relations in animals. I've had cats, dogs, rabbits etc etc etc and just about everything will interbreed with it's parents, siblings etc... and what's a dog that likes to hump a pillow? If we're looking to the animals for what is natural, I think incest would be the first thing people would notice. That and that most animals have frequent multiple partners.
Even in animals, you see procreational problems from incestuous relationships. If a dog impregnates his sister, in his mind, it is spreading the seed wherever he can. I imagine, before the evolution of the large neocortex, humans were probably similar; then we realized, having children with deformities is burdensome and it became socially unacceptable, a sign of inferiority even; to have a disabled child. Harsh, but not untrue. Nowadays, we avoid incestuous relationships primarily because society deems them uncooth, taboo, and children born of them are deformed.
I'm sure if a dog had the mental capacity to think that far ahead, he probably wouldn't go round rutting his sister either.
I don't agree with either but like I said, it's other peoples business and I really don't see how it's right to approve of one and deny the other.
The only reason homosexuality is denied, aside from biblical law, is disgust. It's the same reason incest is denied, culturally. Right now, homosexuality has become something that illicits a disgust response in less people, and it is bcoming more acceptable. One of the reasons for that is that consensual homosexual adult relationships harm nobody. Incestuous ones cross child-parent borders, cross lines of familiar responsibility,l go against the heterosexual biological urge to further the gene pool, and for various reasons, are socially unaccepted -- primarily disgust. However, in reality, as you say, there is no reason that an adult incestuous relationship that does not carry risk of procreation and which has never been abusive nor has started with the rape of a child, is morally wrong other than the societial regulations against it and the words within some religions. Really, there is no genuine, substantial, non-religious reason to assume that such a relationship carries any risk to individuals or society, providing it fulfils the criteria aforementioned.
Still, even if it wasn't considered rotten and disgusting and ungodly, most people won't do it because they simply have no desire to rut with their siblings. They'd rather find someone outside the immediate family.
The only argument that holds any water is the damage to offsprings but like I said, there is so much out there to prevent that, not to mention just get an abortion... which I'm not okay with but I'm betting the people engaged in such a relationship wouldn't have a problem with it.
If a person is having to kill likely disabled babies because she's rutting her brother all the time, that's probably a sign the relationship is no good.
