Despite decades of progress toward gender equality, women remain as the United States’ primary caregivers. Past research has shown how couples and families organize care at distinct life course moments but has not studied how these moments combine to create differences in men and women’s full life courses of caregiving. In this article, I look beyond negotiations within households to introduce a complementary demographic explanation for the gender gap in caregiving-women’s greater likelihood to reside with dependents. A focus on patterns of coresidence is warranted, given the growing diversity of family forms, which may expose women to additional and varied care demands at differing ages. Drawing on data from the 2011 to 2019 American Time Use Surveys, I study how coresidential care demands shape the population gender gap in childcare and eldercare across ages 20-79 and how demands differ for Black, White, and Latina/o women and men. My results show that coresidence with dependents is uneven across the life course, and women’s exposures occur early and late in adulthood, while men are exposed to more care demands in midlife. Patterns of childbearing, partnership, and extended family embeddedness contribute to Black and Latina women’s greater exposure to care demands early in adulthood and White women’s greater exposure to care demands later in the life course. Thus, despite growing egalitarianism within households, the rise of complex families contributes to bolstering population-level gender inequality in caregiving across adulthood.