[I'd like to see Gates donate more of his money towards birth control, condoms, abortions, etc. I'm not trying to make a political point, I'm just stating that the best way to help the human race is to try and stop population growth. Feeding / curing 8 billion people is just going to put further strain on our planet and our resources / food supply. I always tell people that it's better for the environment to live a life of excess than to have a child.]
Actually there is truth in the long term benefit of the whole human race lies in controlled population growth. Currently most regions adopt the economic principle of free market which allows the market to dictate the prices of resources that in principle should see the most valuable resources being used for the most valuable purpose. However, human society has very short term goals which at the end causing the resources still being allocated for wasteful purpose. It is conceivable that all those key resources such as oil, uranium, rare metals etc which supports the existence of modern technology will all be spent on wasteful activities and eventually the human race might spend all of them, lost the grip on advanced technology, and end up being stuck on Earth, waiting for a meteor or other cosmic disaster to wipe us out. Resources is not sufficient because there are too many people need them. If there are less people, more resources are available for everyone and hence each will have a better quality of life. There should be an optimal number of people for current level of technology and resource availability. If we are able to reach out and colonize more planets and stars, then we will be able to support more people. Meanwhile, we should be careful of how much resources we want to spend to make current level of technology sustainable.
Of course, this is a very radical idea and the world is not ready to accept that "you cannot have the number of kids you want to have". But in the more advanced countries, the population growth is usually either stagnant or going negative, so I supposedly in the subconscious, somehow many people already realize that it might be better to have less people.