In a declining economy, it would make sense that fewer children are being born, since the parents on average can't support as many, but in a growing economy, we would usually see many more children being born because times are good, and parents can afford to care for more children - something that isn't being allowed in China.
WWII dragged America (and the world) out of The Great Depression and into the post-war boom. Part of how that happened: American families were forced into having two incomes (so the wife could work in the factory and the husband could be in the army), no new children being conceived/born (what with hubby being off at war on another continent) and war time rationing forced very high savings rates on America -- as high as 50% at one point -- because there wasn't much to spend your dual income on (especially since they were also encouraging people to grow "Victory Gardens"). We went from people moving every 13 months to take advantage of new rental deals (where you got the 13th month free if you could make your rent the first 12) before the war to Levittowns sprouting like mushrooms to try desperately to meet the sudden high demand for middle class housing after the war.
So it's not like something like this has never happened before. Maybe nothing so protracted, but the precedent I am aware of is generally considered to be a good thing.
It would seem to me that warfare is the worst way to solve the population crisis because wars must involves the destruction of existing capitals(Human capitals, mostly) and high opportunity cost(Delaying the introduction of television and other consumer technologies).
I wasn't in any way suggesting that warfare per se was related to my point. My point was that birth rates in America were very low during WWII due to men being off at war and incomes were astonishingly high, while at the same time there was little to spend it on, resulting in high savings rates. So this phenomenon of a growing economy and low birth rate has occurred before, right here in the USA. And the results of that -- the post-war boom time -- are generally looked upon as an idyllic time in America's past. So I don't see why this would be some kind of "problem" to do the same thing in China.
WWII dragged America (and the world) out of The Great Depression and into the post-war boom. Part of how that happened: American families were forced into having two incomes (so the wife could work in the factory and the husband could be in the army), no new children being conceived/born (what with hubby being off at war on another continent) and war time rationing forced very high savings rates on America -- as high as 50% at one point -- because there wasn't much to spend your dual income on (especially since they were also encouraging people to grow "Victory Gardens"). We went from people moving every 13 months to take advantage of new rental deals (where you got the 13th month free if you could make your rent the first 12) before the war to Levittowns sprouting like mushrooms to try desperately to meet the sudden high demand for middle class housing after the war.
So it's not like something like this has never happened before. Maybe nothing so protracted, but the precedent I am aware of is generally considered to be a good thing.