For decades, the United States grappled with a childcare crisis that left American families struggling to secure quality childcare, compromising both children’s development and parental career progress. Here we investigate the impact of childcare availability—and the lack thereof—on US scientists’ career advancement and gender equity in science. We construct a longitudinal database of childcare facilities and their capacities spanning the last twenty years. Leveraging the biennial survey of US scientists and engineers sponsored by the National Science Foundation (NSF) and the National Institutes of Health (NIH), we uncover that over half of US scientists and engineers employed at universities and research institutions work in childcare deserts, that is, areas where the supply of childcare falls significantly short of demand. Despite equivalent exposure to these deserts, the career consequences for male and female scientists are starkly different. Childcare deserts disproportionally reduce women scientists’ likelihood of achieving tenure by 6.8 percentage points, with no noticeable impact on men’s tenure attainment. The lack of childcare explains almost the entire gender tenure gap among scientists with children. Furthermore, this impact is largest in engineering (-19.0 percentage points), followed by that in science and health (-8.2 and -4.9 percentage points, respectively). Our findings highlight the critical role of expanding childcare availability in maintaining research and innovation workforce’s productivity and in reducing the gender gap in science. (author abstract)