I, like everybody, don't approve of incest. Especially since I have a sister of my own, and thinking about HER in that way is repulsive. It's not like there's truly a problem with it, it's just ... Most family members, like mine, are really close, like friends, and they've built such a platonic and familial relationship it doesn't occur to them, and thinking about it just feels WRONG. But if a brother and sister never meet until they're 20, and they want a romantic or sexual relationship, what's wrong with that? They're just two people at that point. They haven't known each other. So what if they're brother and sister? Means nothing.
... You guys lost yet?