The Force and Motion Conceptual Evaluation is commonly used to measure the conceptual understanding of Newtonian mechanics. Several studies have reported a substantial difference in pretest scores between men and women. This study examines the contribution of several prior preparation factors to explain the variance in pretest score and whether these factors explain gender differences in the pretest score. The study examined a large sample (N = 1060) of students taking introductory calculus-based mechanics at the university level. Women outperformed men on most prior preparation and college achievement measures. No significant differences between men and women were found in high school physics taking patterns. Linear regression analysis showed only 23% of the variance in FMCE pretest score could be explained using a linear combination of prior preparation variables. Controlling for these variables failed to explain the gender difference in pretest scores; conversely, the gender difference increased controlling for prior preparation.