One of the major contributors to women earning less and receiving fewer promotions than men, on average, is the motherhood penalty. Sexism, occupational roles, educational opportunities, career trajectories, and other factors have also contributed. For example, despite making up half of the U.S population, women only make up 27% of those STEM field occupations, and 15% of engineers. However, females are also awarded STEM undergraduate degrees at far lower rates—the pipeline to STEM jobs isn’t flowing well.