Research in undergraduate education has documented achievement gaps between men and women in math and physics that may reflect, in part, a response to perceived stereotype threat. My research efforts aimed to reduce achievement gaps by mediating the impact of stereotype threat in introductory science classrooms with a short, values-affirmation writing exercise. The purpose of this research was to (1) investigate and compare the performance of women and men across introductory science sequences (biology, biochemistry, physics), (2) document endorsement of stereotype threat, (3) investigate the utility of a values-affirmation writing task in reducing achievement gaps, (4) provide a meta-analysis of triggers causing stereotype threat, and (5) advise classroom practices to avoid stereotype threat. In this study, analysis of final grades and normalized learning gains on concept inventories revealed no achievement gap in the courses sampled, little stereotype threat endorsement, and no impact of the values-affirmation writing task on student performance.