Recent data show that there are significant disparities among genders and races in the incidence of sepsis. While men are consistently more likely to have sepsis than women, the apparent racial disparities are even more striking, approaching a doubling of the risk for sepsis among Afro-Americans. Most prominent is the risk among black men, the group in which sepsis occurs at the youngest age and results in the most deaths. Potential mechanisms for heterogeneous susceptibility to sepsis include genetic differences, which have been explored according to sex but not according to race, and other social and clinical factors.