The sad thing is that the smartest people (who we would want to be breeding and populating the planet) are the ones that realize how expensive a kid is, how it affects lifestyle, etc.. So they have one, maybe two, often later in life. (I'm not tying to call anyone on here, or their parents, siblings, etc.... dumb. Just saying, its a trend, not an absolute.) Anyways...
The stupidest demographics and fucking hardcore rednecks (anyone seen "The Wild and Wonderful Whites of West Virginia"!?!) have kids pretty much anually, for like 10 years.
So, stasticially the world is getting dumber, and at an exponential pace.