The turning point in the classification history of gender incongruence, occurred with ICD-11 (WHO, 2018) and DSM-5 (APA, 2013) classifications, that respectively introduced diagnostic categories of “Gender Incongruence” and “Gender Dysphoria”. Anyway, adopting a new and universal standard category for gender dysphoria diagnosis, does not resolve the issue of an appropriate epidemiological estimate of the prevalence of the condition. The first task for researchers in the field is to decide whom to count as “trans”, and by what means. Indeed, trans people are a very diverse group (Winter et al., 2016). According to Thompson and King (2015), conceptual basis of epidemiological studies is intrinsically wrong: so, while the aim of research in the field is to promote health and welfare, the means by which trans people are identified actually perpetuate the problem of stigma and inequity in access to healthcare services (Thompson and King, 2015). Trans people face many structural barriers to access gender-affirming care, including lack of insurance, coverage exclusions, coverage denials. Moreover, they usually avoid seeking care out of fear of discrimination. Reisner et al. (2015) propose eight recommendations following the model of the GenIUSS Group, to guide inclusive sex and gender adult population-based research (Table 3; GenIUSS Group, 2014). Indeed, if epidemiologic research allowed us to precisely identify trans people, it would be possible to also detect those conditions that are more frequently associated to gender incongruence, thereby activating more specific interventions aimed at improving these people's quality of life. Having a uniformity of terminology in recognizing these people perhaps can increasingly lead to less discriminatory stigmatization and labelling.