HUMANS: UNNATURAL?

Humans have changed many of the ways that things happen in nature. One of this is altering the birth- death ratio. As it is said in the book, nature usually has its way of controlling the population of a species. It keeps it in balance with diseases and predators. However, humans have made machines and weapons that keep away predators and have used science and medicine to eliminate and defend themselves from diseases.
Going back in history one could see how this would affect society. Men and women would marry young and have babies soon and take in life quickly. They would do this because they didn't know when they would die, a lucky person would live to his fifties, in the middle ages a lucky old guy would be one in his forties, but now, we see men and woman in their eighty's and ninety's and it its actually not that weird. Humans have been able to get their life expectancy much longer and the death rate has decreased. The birth rate, on the contrary is increasing and we are therefore having an overpopulation problem. Women have and have children and our culture is actually suppressing anti-conceptives and drugs that will prevent more children. Why? because it is supposedly unmoral. But isn't overpopulating the world to a point when we are just going to end up killing ourselves unmoral? all we are doing is using up all the resources to a point when the nonrenewable ones will run out and the renewable will no longer be renewable. So we will consume everything and leave all other creatures out of our world. Except, this wont happen because nature will make sure it doesn't. We, as a species will probably starve. the selfish gene inside of us will kick in and make each person fight for its own survival. Nobody will be willing to sacrifice and die for the good of others so you don't get a few healthy humans but you get many mediocre ones. They aren't strong enough to survive and the little strength they have they use it up with survival. So no one is strong enough to survive. We will all die. From starvation.
So what we have thought is smart and were all proud of the fact that we are outsmarting nature is actually our death bed. Unless we do something to stop our over population, we will end all dead, all starved. Well that is if global warming doesn't kill us first.