California and New York are actually among the most inbred states, because they have the largest populations of recent Muslim immigrants, and cousin marriage is more prevalent in the Muslim world than it is in other places: https://en.wikipedia.org/wiki/Cousin_marriage#/media/File:Gl... . There's not all that many Muslims in Alabama or Mississippi; Georgia has somewhat more, probably because of Atlanta's status as a major city that attracts sizeable numbers of immigrants.