This is what I was wondering about, but the interesting part is it's entirely intentional thanks to their 1 child policy. They have a billion people now, but how will the country look 50 years from now when the older generation dies off and all the 'one child' kids grow up? And following up again with the generation after that since they're having more boys than girls.
If there's one thing the Chinese government does is think in the long run, so I've always wondered exactly what the goal with these policies were.
The goal is rather simple: to decrease population growth so that depreciation of capital does not occur at a much faster rate than savings and investment. If you want to raise the standard of living and GDP per capita, you can't have high birth rates. But because of the asymmetric nature of fertility rates in rural-urban China, they had to install a policy that forced fertility rates down instead of the more incremental economic approach observed in developed countries.