Political crises, scandals and dysfunction dominate the global news agenda. Unsurprisingly, therefore, many people missed Britain’s announcement last month that it would spend £600m ($1.133bn) to provide 20 million more women and girls in the developing world with access to family planning. But the British government’s decision, based on research by the Copenhagen Consensus Centre that shows family planning is one of the smartest possible development investments, is a vitally important one. Hundreds of millions of women are unable to choose the number, timing and spacing of their children —...