Projected world population numbers have been boosted from 9 billion to 9.6 billion in 2050 by the demographers at the United Nations in their latest report, World Population Prospects: The 2012 Revision. Why are the projections going up? One big reason is the lack of economic freedom and the rule of law in most high fertility countries. Reason Science Correspondent Ronald Bailey explores recent research by evolutionary biologists on how life-history affects human fertility. Insights from that research suggests increasing economic freedom combined with the rapid diffusion of cheap modern technologies will likely push future population growth significantly below the new projections.