This is an editorial by the Lancet where the gender dimension of Covid-19 is discussed. The editorial highlights how without a global response to the COVID-19 the pandemic might discriminate. Demographic data from small studies are already informing political decisions and clinical research strategies. Women and men are affected by COVID-19, but biology and gender norms are shaping the disease burden. The success of the global response—the ability of both women and men to survive and recover from the pandemic’s effects—will depend on the quality of evidence informing the response and the extent to which data represent sex and gender differences.