Yes. Of course. Look at the birth rate of African countries like Rwanda and Ethiopia. So powerful and prosperous. Oh, wait.
Read 'em and weep.
http://en.wikipedia.org/wiki/List_of_countries_by_birth_rateThe top 50 are all in Africa, with a few notable exceptions like the Gaza strip and Afghanistan. The poorest breed the most, which is why the West is ****ed.
If I was a given dictatorial powers and a mandate to ensure the power and dominance of my country, the very first thing I would do is take away all the contraception and plunge the country into poverty. Within two decades the population would triple, and within a hundred years I would have the French prime minister giving me foot massages in the hopes of ensuring the continued flow of aid to his Principality of Paris, population 500,000.
Look at China. Pound for pound, they're about as powerful as sub-Saharan Africa, in other words the lowest of the low. But they have 1.3 billion people. China alone could match the population of every other Security Council nation and still have 750 million people left over. It's easy to go from being a poor nation to a rich nation: two or three decades and you can have luxurious shopping malls and annoying yuppies, just like America. But it's a long, hard, sometimes impossible process to go from being a nations with few people to one with many. That takes generations, and either poverty or totalitarianism to keep things on track, preferably both.