This is a sensitive subject, but I am interested in the potential genetic and social impacts it may have had so I'm going to go ahead and post it. Allow me to p

This is a sensitive subject, but I am interested in the potential genetic and social impacts it may have had so I'm going to go ahead and post it. Allow me to preface the question by stating that I do not intend this to be a racial, religious, or cultural aspersion - I'm genuinely curious. I have heard (from unreliable sources) that consanguineous marriage is very common in parts of the Middle East, to the point that a male suitor must ask for and be granted permission by a woman's father's brother's sons before being allowed to marry her. This is known as "bint 'amm marriage" This sort of arrangement - first cousins - has a relationship coefficient of 0.125 and is therefore under the threshold studied in TFA, and a quick search leads me to believe that it roughly doubles the chance of a serious birth defect. That said, given the strong cultural forces at work here I suspect that many of these unions are in fact between people who are multiply first cousins, which would magnify the effect. Is anyone here familiar with any studies done on the genetic impact on communities where bint 'amm marriage is practiced? For reference, here's the Wikipedia article on the practice: en.wikipedia.org/wiki/Cousin_marriage_in_the_Middle_East