He did. And we have lines of inbred mice we use for experiments. That doesn't change the fact that inbreeding tends to be bad.

(And Arabs /are/ by and large less intelligent than Europeans. That's quite unfortunate for them, for the Arab countries, and -- given the current migration patterns -- for the Europeans. Inbreeding is one of the preventable reasons for their general lower intelligence. Infectious diseases is another. Lack of certain micronutrients a third. The latter two are fixed by moving to Europe, the former not so much.)