Imperator_DK said:
This taboo is based largely in religious notions which were constructed in backwards societies where there was no feasible way of separating sex from pregnancy, marriage was the only accepted form of having sex anyway, and personal liberty didn't really count for anything.
All those societal factors have certainly changed; why shouldn't the norms change with them?
There's no reason it can't change. I just said genetics is a craps shoot, and shouldn't factor into whether or not incest is allowed.
But it shouldn't be an all-or-nothing decision. It should be handled on a case-by-case basis, and attitudes towards incest should change naturally like they did with homosexuality and the like.
In reality, morals and taboos are inherently relative. Name anything Western culture currently finds abhorrent (rape, incest, pedophilia, mass murder, public torture, bloodsport, animal abuse, slavery, etc.) and I could name several points in history when it was the norm (i.e. not considered immoral). Conversely, there are tons of stuff we consider perfectly fine (premarital sex, eating sacred animals, ignoring beggars, burying the dead, sitting for long periods of time, drinking cold water, being around menstruating women, etc.) which would be considered absolutely despicable at other times and places.
The point is, we're no more enlightened than any other culture. There is no rational way to
prove whether incest (or anything at all) should, or should not, be morally reprehensible.