there must be an element of genetic inbreeding...
morality and faithful marriage aren't just quaint....they are imperative for civilization to progress, and be peaceful.
Rare birth defects common in Gaza due to inbreeding | …
http://vladtepesblog.com/2009/12/18/rare-birth-defects-common-in-gaza-due-to-inbreeding/
They discuss how the quaint practice of Muslim first cousin marriage is responsible for all these birth defects, ... Palestinian teenagers ... cousin inbreeding.*
********* I will not lie and say all Muslim populations are inbred. But Gaza Palestinians are. Many others are too. First cousin marriage is disgusting but it really gets destructive when done generation after generation compounding the problems.