The book Poorly Made in China mentions that the author thinks the census is wildly off its mark and that there are much less people than ascribed to China.
He states that the Chinese have a need to be biggest, most and best in order not to lose face, and reality and truth suffer.
Then why is China trying to reduce its population growth thru its one child policy? The CIA Factbook puts China's fertility rate at 1.54 children born/woman (2010 est.), well below replacement at 2.1.