"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.
The things that characterize Islamist (political Islam, sharia law) culture can also be defined as the leaders encouraging psycho criminal behavior among the followers -- actually it's a requirement.
Mary Tudor married her first cousin, Philip II. No children. The second Queen Mary, the daughter of James II, married her first cousin, William of Orange. No children.
Excessive inbreeding seems to be why the last Spanish Habsburg, Charles II, was an imbecile.
The ancient Egyptians practiced brother-sister marriage. There are cases of it among the Persians--King Darius II (423-404) married his half-sister Parysatis. They had 13 children of which only 5 lived; the older son Artaxerxes II became the next king but was challenged by his younger brother Cyrus--the story is told by Xenophon in his Anabasis (he was with the 10,000 Greek mercenaries recruited by Cyrus).
I would like to see a survey of which Muslim nations and cultures have the most inbreeding. Mostly done via first cousin marriage as far as I know. Turks...probably not so much. Pakistanis very heavy. Muslims in India too probably. Palestinians.... Israeli reports their hospitals get lots of Palestinian children with birth defects from inbreeding. Stanley Kurtz of National Review wrote the first material I saw on this Muzz inbreeding
http://hbdchick.wordpress.com/2011/02/15/cousin-marriage-conundrum-addendum/