SignificanceSocial scientists have long known about the persistent gender gap in voting, with women voting Democratic more than men, and about the much larger racial differences in voting, in which a strong majority of US Blacks vote for Democrats. We show a link between these two voting gaps; the gender gap arises in part because Black women constitute a higher percentage of women voters than Black men do of men voters. This tips women’s votes toward Democrats. Other research shows that premature death, incarceration, and disenfranchisement remove Black men from the population and/or the electorate. While social science research has documented many racial disparities, one little-recognized consequence is that they contribute to the consistent post-1980 gender gap in voting Democratic.