I've been wondering for a while now why China doesn't back off to a two-child policy. Most of the problems caused by the one-child policy would go away or be greatly eased, and yet the population would still attain stasis. I've put it down to organizational inertia.
Really, given that population trends in most countries are headed towards or are under replacement level, they could probably just ditch the n-child policy altogether, but I don't think the government of China is capable of making such a momentous change any time soon.