Somewhere Julian Simon is smiling. In the 1970s and 1980s, the World Bank, the Club of Rome, author Paul Ehrlich, and the United Nations predicted catastrophe if China’s government couldn’t stop its people from having babies. Simon argued from his post at the University of Illinois that this was wrong. He said the problem wasn’t too many Chinese but the political and economic system oppressing them. Simon even predicted in 1985 that if China opened its economy to market forces, the growth might leave China facing a labor shortage.

Well,...