The documented underrepresentation of women and homosexuals in leadership roles necessitates a more thorough investigation of its underlying factors. Our study employs both a lab-in-the field and an online experiment to examine a prominent theory that seeks to explain the sexual and gender disparities in political leadership ambition. Specifically, we explore the notion that women and homosexuals may exhibit a higher reluctance to engage in competitive environments. Within the framework of an experimental political context, we consider two distinct subject pools: highly politically active individuals and participants from an online labor market. By controlling for a variety of internal and external factors and preference-based indicators, we establish that there are fundamental sexual and gender behavioral differences, stemming from differences in underlying psychological abilities and differences due to the nature of electoral competition. We find that priming individuals to consider the competitive nature of politics has a strong negative effect on women’s and homosexuals’ interest to run for a political office, but not on men’s and heterosexuals’ interest, hence significantly increasing the gender and sexual gap in leadership ambition. While the gender gap also persists in the online experiment, it is noteworthy that our research uncovers a contrasting trend among homosexuals. Specifically, their intent to engage in politics follows a divergent trajectory.