The relationship between gender and health inequalities is potentially complicated, raising questions for health and social research, practice and policy. In this paper, I use two population health case studies - obesity and smoking - to explore the interplay between gender and socioeconomic position. The cases show that, on its own, neither dimension of inequality affords a comprehensive picture of these significant risks to public health. Furthermore, historical change in the socioeconomic and gendered distribution of these health risks suggests that gender is best considered as a dynamic and layered form of differentiation, rather than as a simple or stable dichotomy. A more nuanced approach to the analysis of gender and health has the potential to generate both more fruitful research and more effective health and social policy.