chinangel said:
let's say that you have 2 kids, and they're around 14-16 years old and you discover that they're attracted to each other.
Now key here: they're of the same gender, either 2 boys or 2 girls so the issue of an inbred child is non-existent.
As their parent, what would you do?
Me? Support them. I don't see why i should say 'no' to two people loving each other, even if they happen to share genes. Love is love, right?
I would do what I could to dissuade them from acting out on their attraction. As a parent my first duty is to ensure that they are given the best chance I can so they can survive and thrive in the world. Incest is a huge impediment to that, regardless of the genders of the participants.
First, it may or may not be legal in the area they're living. This means the participants need to keep this a closely guarded secret or potentially face legal action taken against them. Keeping a secret like this is going to be a source of stress for the rest of their lives and stress is an unpredictable thing. As a parent I have to be extremely wary of letting a secret like this take root.
Second, it is a social taboo regardless of legality. People have a natural instinct against incest that is regularly codified into their cultures. So even if it is legal in the area it is highly unlikely that people will be accepting of it, meaning that it will still need to be kept a secret. In which case the stress mentioned above is present, albeit from a slightly different angle. Again, as a parent it's my duty to give them the best possible chance in life, and letting them keep a social taboo secret for the rest of their lives is something that is not going to help them. Add to this the social taboo in many places against homosexuality that is still incredibly strong.
Third, they are going to spend the rest of their lives being forced to interact. If their sexual relationship ends poorly they look forward to a lifetime of jilted lovers that can't simply ignore the presence of the other; they're going to have to interact when it comes to such things as the death (or incapacitation) of parents and other relatives, divvying up parental belongings, legal issues surrounding who has power of attorney and the like, etc. This can be stressful enough when there is no sexual relationship involved. My mother's family is completely dysfunctional without any sexual relationships in place, so by having grown up in that sort of situation I have experience that my children would lack - I can point out specific instances of dysfunction within their own extended family as potential outcomes for their current hoped-for actions.
Fourth, they're KIDS. They're 14-16. In 10 years they are going to be completely different people. Even if they have an amicable ending to their sexual relationship they're going to look back on it differently. They're too young to be entirely certain if what they're experiencing is what they're going to grow into. They may find out that they're actually homosexual or bisexual, but they may find that they actually aren't - that the attraction is something else. If they're different ages, is the older one in a position of "power" - where the younger one idolizes the older one in some way? Does the older one initiate the situation, and does it flatter the younger one? Is there an undercurrent of fear in the relationship - that they feel a same-sex attraction but are afraid to act on it? And so the idea that someone within the family, who would be willing to keep it a secret, would become a viable partner to act on the same sex attraction? Etc. This can lead to the bad break up if one partner begins to feel exploited.
I can go on, get more detailed and more complex, but really it all comes down to the fact that incest is not acceptable in most societies, so even if I was accepting of it (which I'm not) as a parent I would have to do what I could to dissuade it, for the long term good of my kids.
Now, what I WOULD try to do is to encourage them to look for same sex partners outside of the family. I would make it crystal clear that I'm dissuading the INCEST, not the SAME SEX attraction. And I'd be completely honest with them why I'm dissuading them and entirely avoid the "Argument from Authority" fallacy, because all that would really do is to make them try to stand up to authority by actively defying me.