That ain't all they bring.
"Risk of mental retardation increases . . . 400 percent . . . IQ is 10-16 points lower . . . abilities related to social behavior and empathy develops slower in inbred babies"
There's a lot more to this than cultural . . . consanguinity (inbreeding) among zealous Sharia Law Muslims.. see map below.
"Consanguinity is a deeply rooted social trend among one-fifth of the world population mostly residing in the Middle East, West Asia and North Africa, as well as among emigrants from these communities now residing in North America, Europe and Australia . . . ." source: National Center for Biotechnology Information, U.S. National Library of Medicine
google: "Nicolai Sennels" "The connection between Muslim inbreeding and terrorism"
Take your pick yes or no. It's mostly yes.
consang.net Global prevalence of consanguinity
Coincidence? I don't think so.
From an Internet source:
"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. "
My emphasis.
.. more from same source
Danish psychologist Nicolai Sennels:
. . . close to ninety percent [of the suicide bombers were] suffering from severe illness such as blindness, cancer, missing limbs or leprosy. Many Muslim societies . . . have a low social acceptance of handicaps and severe illnesses . . . being physically handicapped or mentally retarded often leads to exclusion . . . and becoming a martyr might be the only chance of achieving social recognition and honour  if not just a way to end the pain of being socially isolated (which is especially traumatizing in collectivist cultures like Islam). Al Qaida's use of people with Down's syndrome might be another unpleasant side effect of the many chromosomal illnesses resulting from inbreeding between first cousins. People with low intelligence (because of inbreeding) might also be easier to brainwash with fundamentalist Islam.