Efforts to promote equity and inclusion using evidence-based approaches are vital to correcting long-standing societal inequities that have disadvantaged women and discouraged them from pursuing studies, including in many STEM disciplines. We used 10 years of institutional data from a large public university to investigate the grade point average trends in different STEM disciplines for men and women who declared a major and then either completed the degree or dropped the major after declaring it. We found alarming trends, such as that women who dropped majors on average earned higher grades than men, and in some STEM majors, women who dropped the majors were earning comparable grades to men who persisted in those majors. While these quantitative findings call for a deeper understanding of the reasons women and men drop a major, we provide suggestions for approaches to make learning environments more equitable and inclusive so traditionally excluded groups can have a higher sense of belonging and thrive.