Part One: Mexico
Nuclear families in nations as apart as Asia and Latin America are beginning to show signs of break-down, following the West into a more transient and multi-layered style of family life.
In Mexico City the next stage of this social evolution is already taking place. New laws and attitudes are putting the capital at the forefront of that shift.
We meet some of the human faces behind the statistics and ask them about life at the leading edge of what some experts think may be a global transition.