In many democracies, gender differences in voter turnout have narrowed or even reversed. Yet, it appears that women participate more in some circumstances and men in others. Here we study how life trajectories – specifically, marriage and having children – will impact male and female turnout differently, depending on household-level context. To this end, we leverage a unique administrative panel dataset from Italy, an established democracy where traditional family structures remain important. Our within-individual estimates show that marriage increases men's participation to women's higher pre-marital levels, particularly so in low-income families. We also find that infants depress maternal turnout, especially among more traditional families, whereas primary school children stimulate paternal turnout. Exploring aggregate-level consequences, we show that demographic trends in marriage and fertility have contributed to recent shifts in the gender composition of the electorate. Together, our results highlight the importance of the family as a variable in political analyses.