[fireman15]

Islam is the world’s fastest growing religion. This is due mostly to their high fertility rate.

“the number of Muslims is expected to increase by 70% – from 1.8 billion in 2015 to nearly 3 billion in 2060.”

http://www.pewresearch.org/fact-tank/2017/04/06/why-muslims-are-the-worlds-fastest-growing-religious-group/

[Mrs. Don-o]

Yes, Islam is the fastest-growing religion. They have a higher fertility rate than, say, Christians in post-Christian Europe or North America, but they do not have the highest fertility rate --- that would be the black Africans of Sub-Saharan Africa, who are predominantly Catholic, Protestant, Pentecostal (these three are Christian) and Animist..

Here's a Fun Fact: Throughout the ummah (the Arabic term for the global Muslim community), the average number of children born to women is falling dramatically.

And here's another one:

With extremely rapid fertility decline — and the descent into sub-replacement fertility — a number of Muslim-majority populations are already set on course for very rapid population aging.

Those two are worth the click. And there's a lot more proof for dramatically falling Muslim demographics here (LINK)