Women are having fewer children than ever before, and population growth has slowed from 2.0 to 1.3 per cent in 30 years. But large families in the recent past mean that there are many more women of childbearing age. Global population is still rising by about 78 million people a year. Half the world is under 25 and there are over a billion young people between 15 and 24, the parents of the next generation.