I am conflicted on this subject for the same reasons that someone else in this thread brought up. I have some libertarian-esque leanings on the social side of things. If consenting adults are committing incestual relations with each other, I really don't care. It's none of my business. That said, we don't like in a purely free market economy so if god forbid two relatives have a baby and it turns out to have down's syndrome, us taxpayers have to foot the bill for the product of their incestuous pleasures.
But when you go down that line of thinking, you could very well justify eugenics. And that is a line that I'd rather us not go down. It's tough to say where you draw the line between liberty and having to conform to societal norms. Even if we lived in a libertarian society, the actions of people still do affect others at least on an indirect level. As humans we are social animals and interconnected and interdependent on another. Think about it. Even in a so-called "perfect" libertarian world where there's no income tax and small government, every single time a person chooses to be an underachiever and not live up to their productive potential, the GDP of the country suffers (since they won't be contributing to the economy all that much). We are all interconnected no matter what. We do not live in a vacuum.
