Effective science instruction and associated student learning is reliant upon a strong foundation of teacher content knowledge. This study of the "Praxis?" General Science Content Knowledge Test from May 2006 to June 2016 investigates content knowledge of 28,688 general science teacher candidates. Examinees performed well on "Life Science" topics while "Earth & Space Science" was identified as an area in need of support. Analysis of the assessment revealed differences in achievement associated with undergraduate major, gender, and ethnicity. Test-takers with STEM majors demonstrated stronger content knowledge than their out-of-field counterparts, that men outperformed women in the study, and White test-takers lost fewer scaled points than Black and Hispanic candidates. To strengthen recruitment and retention efforts, recommendations include reviewing our findings for alignment with state standards. This will facilitate development of comprehensive content knowledge professional learning experiences that will be used as an anchor for focused support on those topics where test-takers tend to demonstrate lowest proficiency.