When I was in my early 30's, I was gung ho on ZPG, Zero Population growth, even going so far as to writing on the subject--believing that every one needed to replace themselves, no more, no less, in order to have a healthy planet. I have not stopped believing in that premise but there are some out there who are not cooperating.
Here is a video that says we better get moving or our entire country, as we know it now, will be totally different in just a few decades.
See the video on why we might need more American kids.
Muslim Demographics