Western countries with ageing populations are in the grip a cruel irony. At the same time as having more old people than ever to support, youth unemployment is at its highest levels for a generation. As many of these countries go into elections this year, this column warns against populist politics that panders to the grey vote, and instead calls for leadership that puts the family first.

Why do people form long-lasting marital unions? This column presents new insights on what makes a family stick together. Families dominate more promiscuous pairs, in the sense that they can achieve greater survivorship and enhanced genetic fitness. The column suggests that this might provide an evolutionary explanation for the origin of religion as an institution to protect the family.