To think about it, it doesn't take that many countries to make a serious impact in the world - China and India account for a hefty share of Earth's population, if they prefer boys over girls (can't say i don't understand them, with government trying to prevent demographic explosion in every way possible people use every avaliable means to get a child who they think he'll be able to provide them for when they get old). And yet the piopulation there is STILL rising, despite the 1-kid-per-family policy thatr is encouraged and unbalanced structure (too many boys who don't get to ... mate).
Makes me wish the Earth was just 50% larger with current population - there'd be fewer wars, etc., and these issues woudl be less of a concern.