First, to get the medical side out of the way, I can see good genetic reasons for not marrying one's first cousin, reasons which may indeed be powerful enough to justify measures banning or restricting the practice. I don't feel qualified to judge that, and for the present purpose I'm not interested in it either. It's clearly less than optimal, like having parents over fifty, but whether it's a sufficiently bad idea to pass laws about it I just don't know.
What I'm interested in here is the visceral ickiness some people clearly feel at the idea of first-cousin marriage - the feeling that it breaks some powerful incest taboo, perhaps just a notch down from marrying one's sibling, child or parent.
I wasn't brought up to feel like that at all, and I'm curious as to why not - or, conversely, why other people do. Since these things are cultural, where are the cultural dividing lines, in terms of geography, generation, or belief systems? My impression is that the taboo feeling is stronger in the States, but I also think that in the UK it's stronger with the younger generation than with my own or older. There are also ethnic groups within the UK where first-cousin marriage is common, notably within the Pakistani community where I believe it runs at over 50%, and of course that has meant that the subject has inevitably become embroiled in rows about race, religion, etc. Has that altered the broader terms of the debate?
In short - as I see it, when I was growing up first-cousin marriage was considered unusual but in no way taboo, at least in my little bit of the world. I think it was even seen as romantic. Now, the feeling that it's taboo is much more widespread.
How does this tally with your experience of your own and other people's opinions? Have things changed?