Michael, China has had a one child per couple (in some cases two) policy in place since the 1960s. They realized long ago that without severly limiting and ultimately reversing their population growth there would catastrophic consequences in the very near future for them. Because they have a dictatorial centralized government, they were able to force compliance. Get pregnant one time too many, and you will loose housing, job, health coverage, etc. This policy is one reason for the gender imbalance: their society regards female children as worth very little compared to a male child, though this is changing. It's also why the many children killed when last year's earthquakes caused schools to collapse represented an unimaginable horror. For most people the child they lost was their only child.
India tried and failed to limit population growth through financial incentives. The two nations, India and China, between them have more than 40% of the world's population. The gender imbalance in China does cause difficulty even now, but the real problem with limiting population is economic, the same as the one that afflicts wealthy nations like the US. The percentage of old people becomes increasingly larger than the younger productive population that supports them. This is the root problem with the US Social Security and Medicare programs, and is also why there are policies aimed at increasing the flow of younger, tax-paying immigrants.
However you look at it, the geometrically increasing world population spells disaster in many ways. There is an excellent perspective in the analogy of a large lake which starts with just one lily pad, but has a doubling of the number of lily pads every day. The day before the lake is completely strangled by lily pads, only half the lake is covered. This is about where we stand regarding population. Not just climate change and coastal flooding, but an absence of drinking water, famine, and the massive movements of thirsty starving people that will result in global political destabilization and conflict. Meds don't change reality. They provide temporary amnesia. Remember when there were only 3 billion people? Just a few decades ago. We will very soon hit 8 and then 10 billion, and then 15 billion. We add the equivalent of the population of NYC about every day. Every day, and that's now. Soon it will be an even larger number. It's very,very bad. Enjoy what's left, because it will not be here long. I wish it were not so, but it is. I am o;d enough and have traveled enough to remember clearly the natural world of the 60s and 70s. We will not see anything as fair and lovely again.