Yes, and for all of their cosanguinity their congenital defects and genetic diseases are off the charts. It’s what happens when the family tree doesn’t branch.
CC
The author of the quote below is Danish psychologist Nicolai Sennels and his articles and others are laboriously sourced.
"If there are two things that characterize Islamic culture, they are terrorism and inbreeding. The latest research shows that these two things might be closely connected . . . First cousin marriages have been the tradition in many Muslim families for innumerable generations. Such marriages increase the risk of negative mental and physical consequences . . . Risk of mental retardation increases with 400 percent (Proceedings of the National Academy of Science, 1978 “Effect of inbreeding on IQ and mental retardation”). Research shows that the IQ is 10-16 points lower in children born from blood related parents and that abilities related to social behavior and empathy develops slower in inbred babies (Indian National Science Academy, 1983 “Consanguinity Effects on Intelligence Quotient and Neonatal Behaviours of nsari Muslim Children” [pdf]). Such facts might make several pieces fall into place for many people . . . People with low intelligence (because of inbreeding) might also be easier to brainwash with fundamentalist Islam. "
From Internet sources. My emphasis.
Shame and damnation be upon the Islamists. If ISIS forms a califake or whatever that attracts millions it invites the question, "How many MOABs will it take to end this vile bullshit for another 1,000 years?"