I remember going to a family reunion over in Bufffalo, NY about 12 or 13 years ago. One of my 'cousins' (whom I had never met before) was there and damn was he gorgeous! We were trying to figure out how we were related and it turned out that my mother and his mother were first cousins....so I guess that made us second cousins? Anyway, we both decided it was a little to close for comfort to pursue anything.
I think continual 'inbreeding' in any culture eventually becomes a problem. Around here there's alot of Old Order Amish & Mennonites where first cousins marry and believe me, it's starting to show.
One thing about being a Witness: at least they have cars and assemblies so you can meet other Dubs that you're not related to.