What we really need is quality over quantity. Sure we may have lots of people but most of them are totally worthless and would die over night if they had to live outside. What we need is rigorous eugenics with long term vision while the Chinese shore up their numbers of worthless peasants and get the pacifying crowd revolts they are constructing for themselves.
(typos fixed!)
Eugenics is not the answer. Humans contain such little genetic variation compared to other animals. The development rate of humans is too long, it takes six years after birth of a human child to be at the same age of development as most other newborn animals, approximately thirteen to sixteen years on average after birth to become capable of reproduction, and are not truly adults until about 20 or 22 years after birth. This also denies one of the most basic facts of humans: intelligence. It means that the only way to succeed is superior genetics, which isn't the case. Superior genetics is a fallacy. They can fail, the brain can develop poorly--and a worthless brain harbors a worthless body (and let me tell you, I've met some worthless bodies). Genetic diseases and most other diseases are mutable. You may be able to weed the lot out, but most bacteria and viruses will adapt to new conditions.
The intellectual flexibility of humans is what makes nations conquer other nations. Nations succeed because they possess resources and knowledge to use, greater transmission of information, and so on. The people in those nations that succeed desire an explanation for their power. It sounds better when they say it was predetermined: God/Allah/Flying Spaghetti Monster favors us, we are led by the descendant of the sun god, we have superior genetics.
Do you know why the US military is one of the best in the world? It's not genetic screening and gene therapy and eugenics at play. It's hardcore training. While the best equipment and technology is available, so is the training to use it. The same goes for the Israeli Air Force, one of the best trained air forces in the world; their pilots are hands-down better than American pilots.
The cost is also a terrible price to pay. You limit population growth to an extreme. The cost also, for research of genetics and disposal of "genetically inferior specimens", is outsanding. It's just damn cheaper to just to education them then work is to they pop out of the vagoo doing calculus. You also pay a humanitarian price. People, no matter how much propaganda is given to them, may and will ultimately reject it.