Gender equality and sick leave among first-time parents in Sweden.

To examine gender equality in the family and sick leave among first-time parents. : Heterosexuals who became first-time parents between 2002 and 2009 ( = 223,332) were identified in national registers. Gender equality in the family was evaluated by parental insurance and income from gainful employment representing the domestic and work spheres respectively and was defined as each parent contributing 40-60% of the family total. The risk of a new medically certified sick-leave spell (>14 days) was evaluated by hazard ratio (HR) using the Cox proportional hazard regression, adjusted for demographic and socioeconomic factors. : Gender equality was associated with an increased risk of sick leave compared with traditional roles where women had the main responsibility in the domestic sphere and men in the work sphere (HR 1.30 in women and 1.19 in men). In addition, situations with one partner exposed to double burden or untraditional settings were associated with an increased risk.