Check out this story from The Weekly Standard. It is a very long article with a ton of facts talking about fertility rates around the world are dropping in industrialized countries, thanks to some of them like China adopting the "one child policy" that here is America, we are adopting voluntarily. In (my opinion)since people in this country seem to having kids later in life, partying and seem to be enjoying the "Generation Me" mentality.
By adopting this policy, the average age of the country will rise, the birth rate will lower, the population as a whole will drop significantly in the long term, and the only reason why America's population has been holding pretty steady and rising slightly every year is because of the influx of immigrates. The love having babies.
This is a quote from the article: Social changes have affected the fertility rate, too. Some of these changes are small and simple—like the evolution of car-seat laws, which make it difficult to transport more than two children. Some—like the rise of the educated woman—are massively complex...
One of the best predictors of fertility is education: The more educated a woman is, the fewer children she will have. The total fertility rate for American women without a high school diploma is 2.45. With each subsequent level of educational attainment, fertility falls—it drops to 1.6 for women with a graduate degree. One of the drivers of our fertility decline was the making of college de rigueur for middle-class women.
But like I said, read the whole article, it's very interesting.