[Beijing, September 20. Image via Getty]

A Chinese parent plays with her baby during a baby swimming contest in Beijing on September 20, 2009. At 1.3 billion, China's population is the world's largest, but it has been kept in check by a policy forcing most urban couples to have only one child, though the country still has about 20 million births a year. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)