The US economy has been hampered over the last four decades by three trends: the productivity slowdown, the Great Moderation, and jobless recoveries. Economists seeking to explain these phenomena have generally looked to the impact that technological change has on labour demand. This column proposes an alternative explanation: the rise and stabilisation of women’s participation in the workforce, one of the most notable developments in the post-war US. Excluding gender differences in aggregate models of the US economy obscures our understanding of business cycle behaviour and economic performance.