[identity profile] mmcirvin.livejournal.com 2014-10-17 11:07 pm (UTC)(link)
I remember being surprised about that when I applied for a marriage license. You can't marry your uncle or aunt in Massachusetts, but you can marry your first cousin. There are many US states where you can't, though.

[identity profile] roseembolism.livejournal.com 2014-10-18 11:14 am (UTC)(link)
This actually came up when Judge Richard Posner struck down Wisconsin and Indiana's anti gay marriage laws. In destroying the statess argument they had an interest in biological reproduction, Posner pointed out that the state allowed sterile people and first cousins over the age of 65 to marry.

Listening to Posner simply run rings around the state attorney was great by the way: http://www.slate.com/blogs/outward/2014/08/27/listen_to_judge_richard_posner_destroy_arguments_against_gay_marriage.html