The long term demographics in China were always going to be interesting because of the 1 child policy that kicked in during the 1970s. Currently there are more males than females because culturally the Chinese prefer to have male children. The smaller pool of Chinese women comes with prerequisites. For a Chinese woman the man must be taller, older, higher educated and earn more money than her. So with lots of smart, well paid women in China who cannot find a suitable man, they are simply not having children. This has compounded China's already low birth rate of 1.55 (replacement is 2.1, India is 2.65). If a strong growing workforce is the engine of an economy then longer term the Chinese economy is looking interesting.
The demographic change to hit China is an interesting topic. I posted a wire last month that discussed how China's loosening of its one-child policy stands to be its best economic stimulus plan yet. The extra 9.5 million mouths to feed each year will unlock a new wave of demand for commodities and consumer goods. http://seekingalpha.com/article/1637592-chinas-2-child-policy-will-set-these-super-hot-stocks-ablaze?source=feed_f