The debate over the demographic trends in the United States and other wealthy countries can be described a debate between those who care about our children and those who want more of them. This is apparent once a little logic is applied to the tales of demographic disaster being hawked by those concerned about declining birth rates and greater longevity.
The basic story is that we are seeing a declining ratio of workers to retirees. This is supposed to mean that our children and our grandchildren will have an unbearable burden supporting us in our old age. In the United States, the story is that we now have about three workers for each retiree. In 20 years' time, this ratio is supposed to drop to 2:1. In countries like Germany and Japan, the decline is somewhat greater, since they have lower birth rates, and in the case of Japan, less immigration. They also have somewhat more rapid gains in longevity.
This basic story has managed to make otherwise sane people seriously fearful about their country's and the world's future. A quick statistic that should alleviate the fears is that the ratio of workers to retirees in the United States was 5:1 back in the 1960s, far higher than the current 3:1 ratio.
That's right: ageing is not new. As a result of modern medical technology and high living standards, life expectancies have been increasing for a long time. And, just as no one now blames our current economic problems on the larger percentage of retirees in the population, there is no reason to believe that, in 30 or 40 years, that it will be an important factor depressing living standards.
http://www.guardian.co.uk/commentisfree/cifamerica/2011/jan/20/economics-usa