The population of Asia is growing both larger and older. Demographically the most important continent on the world, Asia's population, currently estimated to be 4.2 billion, is expected to increase to about 5.9 billion by 2050. Rapid declines in fertility, together with rising life expectancy, are altering the age structure of the population so that in 2050, for the first time in history, there will be roughly as many people in Asia over the age of...