IN the eternally recurring debates about whether some rival great power will knock the United States off its global perch, there has always been one excellent reason to bet on a second American century: We have more babies than the competition.
Its a near-universal law that modernity reduces fertility. But compared with the swiftly aging nations of East Asia and Western Europe, the American birthrate has proved consistently resilient, hovering around the level required to keep a population stable or growing over the long run.
Americas demographic edge has a variety of sources: our famous religiosity, our vast interior and wide-open spaces (and the four-bedroom detached houses they make possible), our willingness to welcome immigrants (who tend to have higher birthrates than the native-born).
And it clearly is an edge. Todays babies are tomorrows taxpayers and workers and entrepreneurs, and relatively youthful populations speed economic growth and keep spending commitments affordable. Thanks to our relative demographic dynamism
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