ABSTRACT

Formal epidemiological studies on the incidence and prevalence of gender identity disorder (GID) or transsexualism have not been conducted. Accordingly, crude estimates of prevalence have had to rely on indirect methods, such as parental endorsement of behavioral items pertaining to GID on omnibus questionnaires for children and youth or the number of adult patients seeking contra-sex hormonal treatment or sex-transformative surgery at hospital- or university-based gender clinics. Data from child and adolescent parent-report questionnaires show that the frequent wish to be of the other sex is quite low but that periodic cross-gender behavior is more common. In the general population, cross-gender behavior is more common in girls than it is in boys but boys are referred to gender identity clinics more frequently than are girls. Prevalence estimates of GID in adults indicate that it is higher in natal males than in natal females although this may be accounted for by between-sex variation in sexual orientation subtypes. Prevalence estimates of GID in adults based on clinic-referred samples suggest an increase in more recent cohorts. It remains unclear whether this represents a true increase in prevalence or simply greater comfort in the seeking out of clinical care as professionals become more attuned to the psychosocial and biomedical needs of transgendered people.