Social disapproval and the sanctions incurred by athletes who practice activities perceived as incongruous with their gender in particular explain the gender differences seen in the practice of sport and physical activity. In sport, stigma is often associated with sexual orientation (Schmalz et al., 2008) and the gender identity of athletes is questioned. This study aims to investigate how adolescents (re)define their gender identity according to their sport. Sixty-eight athletes (18 male and 50 female) with an average age of 14.5 years (SD = 2.59 years) completed the French version of the Multidimensional Gender Identity Assessment (Évaluation Multidimensionnelle de l’Identité de Genre : EMIG). The results show a cognitive asymmetry in the self-evaluation of gender identity that is explained more by the social hierarchy between males and females than by the type of activity. Thus, athletes practicing activities contrary to gender stereotypes seem to reinvent their gender identity rather than to invert it.