If what is reported in this WaPo article is accurate, if fertility rates are really dropping in Muslim lands as they have elsewhere, something is going on with the human race - potentially something very scary. See this RealClearPolitics article by David Ignatius of The Washington Post.
For a decade or so we thought population declines were only happening in developed countries. Most Muslim countries aren't developed. Nevertheless their population rates are falling and so are their marriage rates. So far every region except sub-Saharan Africa has been heard from.