[Girchuck]

You are aware that the population of many European countries is decreasing, right?
How did they achieve this decrease without any restrictive "one child" policy? (by the way, China population keeps growing, only the rate of growth is decreased)
The answer is: universal acceptance and easy availability of all forms of birth control, and least restrictive sexual mores. Liberate the women from "be fruitful and multiply" mentality, and you won't need to do anything else to get population growth under control.