This study contributes to the understanding of gender differences in economic outcomes by analyzing the relation of non-binary gender expression and biological sex to competitiveness, performance, self-confidence, risk preferences, and beliefs about them via two experiments conducted on Prolific. The first experiment examines the relation of biological sex and gender expression to preferences, while the second experiment analyzes the effect of biological sex and gender expression of others on the beliefs about their preferences. These experiments together show who may be disadvantaged due to their preferences and who may be discriminated against due to beliefs about their gender. The results point out a mismatch between the determinants of preferences and beliefs.