China's population of 1.1 billion is growing. China's population is also aging: the elderly may number 300 to 400 million by 2050. Efforts to reduce the population growth will increase the proportion elderly. To increase the size of the work force, a substantial delay in the age of retirement may be necessary. To reduce the number of births, some judicious mix of delayed childbearing and lower fertility will be required. The population policy choices made in China will determine the future size, age composition, employment structure, and family patterns of a population that currently includes more than a fifth of the world's people.