FORTUNE -- Fair pay and employment for women are not feminist issues; they're economic ones. Data from a recent World Economic Forum report displays just how essential equal wages can be. A nation's competitiveness is determined by its talent pool; ignore half the pool and the economy suffers. Japan's GDP stands to gain 16% if it closes its gender employment gap, according to a report by the U.N.'s Economic and Social Commission for Asia and the Pacific. The same report estimates that by limiting women's career options, the region's economies lose out on as much as $46 billion a year.