Gender identity is a collection of thoughts and feelings about one's own gender, which may or may not correspond to the sex assigned at birth. How this sense is linked to the perception of one's own masculine or feminine body remains unclear. Here, in a series of three behavioral experiments conducted on a large group of control volunteers (N = 140), we show that a perceptual illusion of having the opposite-sex body is associated with a shift toward a more balanced identification with both genders and less gender-stereotypical beliefs about own personality characteristics, as indicated by subjective reports and implicit behavioral measures. These findings demonstrate that the ongoing perception of one's own body affects the sense of one's own gender in a dynamic, robust, and automatic manner. Gender identity is a collection of thoughts and feelings about one's own gender, which may or may not correspond to the sex assigned at birth 1-5. This multifaceted, subjective sense of being male, female, both, or neither occurs in our conscious self-awareness, but the associated perceptions and beliefs can also be largely implicit 3-5. In the past, gender identity was conceptualized as a male-female dichotomy; however, current theories consistently postulate that gender identity is a spectrum of associations with both genders 1,3-6. There is also a general consensus in the field that gender identity is determined by multiple factors, such as person's genes, hormones, patterns of behaviors, or social interactions 4-8 ; and that the sense of own gender (e.g., "I'm male") is closely linked to one's beliefs about males and females in general (e.g., "males are competitive"), as well as to the associated beliefs about own personality ("I am competitive") 1,3,6. The specific content of such beliefs and their strength contribute to what it means for a given person to be male or female in a given sociocultural context, which in some cases hinders the realization of one's full personal or professional potential. Although gender identity has a profound impact on our lives, little is known about how this sense is formed or maintained. A better understanding of the neurocognitive mechanisms of gender identity is also important in the context of gender dysphoria (DSM-5 9 ; gender incongruence ICD-11 10), which is characterized by the prolonged and clinically relevant distress that some transgender individuals experience due to inconsistency between their sex assigned at birth and their subjective sense of gender. Various observations suggest that gender identity and the perception of one's own body are tightly connected. For example, people with gender dysphoria (see above) often avoid looking in the mirror, hide their bodies under loose-fitting clothes, and seek hormonal and/or surgical procedures to adjust their physical appearance to meet their subjective sense of own gender 6,11,12. Moreover, among individuals whose gender identity matches their sex assigned at birth, mastectomy and androgen deprivation cancer therapies, which both ...