As people become more well off and have an acceptable standard of living, evidence shows that birth rates tend to drop. (There will always be a few people who want lots of children and some who won't want any.)
IMO strategies to help less developed nations get on their feet, improve overall health and education, and lift the standard of living will go a long way to lowering the birth rate and slowing population growth.
China had a particular set of problems - small areas of habitable land relative to the population, an exploding population and general poverty. It had a regime in place where it could impose such a restriction on people. Western democracies would not be in a position to do the same and nor do they need to. They do not have exploding populations and some developed nations have declining populations.
Declining populations bring their own problems. That fact makes it more imperative to stabilise the global population so that we maintain a sustainable ratio of young people to old. The world will find it very difficult if the demographic profile were to suddenly shift to 80% over 50 years of age.
Posts like we've seen the last few days alleging prominent people are advocating all sorts of weird and wonderful things are stupid - although they help sort out the serious posters from the trolls.
On the other hand, addressing the world-wide population problem is a real issue and the subject of serious consideration by policy advisers and other important contributors to society.
