Number three is economic conditions, that make it difficult for women to get proper pre-natal care.
Number two is pollution, such as contamination of water sources or living near factories that emit dangerous byproducts.
But the major reason for birth defects is inbreeding.
Some 35-40% of Egyptians marry their own cousins, according to the article. And they are not alone.
This 2005 study says:
One distinctive feature of Arab families is the relatively high rate of marriage between relatives (in particular, between cousins), a practice known as consanguinity. Marriage between relatives is particularly high in Sudan, Libya, and Saudi Arabia, where 40 percent to 50 percent of ever-married women ages 15 to 49 are wed to their first cousins. These consanguineous marriages are not necessarily arranged marriages; they may well reflect the wishes of the marrying partners. But marriage between close relatives can jeopardize the health of their offspring, as can marriage among families with a history of genetic diseases.A 1997 study in the UAE found:
The consanguinity rate in the UAE has increased from 39% to 50.5% in one generation.
Israeli Arabs have high rates of consanguineous marriages as well.
This is a major health crisis in the Arab world that falls under the radar.
The sad part is that this is a problem that is relatively easy to fix. Yet none of the people we see so often who pretend to love the Arabs so much seem to care when Arab problems cannot be blamed on Israel.