Prevalence, incidence and sex ratio of transsexualism.

Frequency figures for transsexualism, concerning incidence, prevalence and sex ratio calculated in the 1960s and 1970s, were compared with recent reports. The incidence figures remained constant over time, whereas the prevalence figures tended to increase during the review period. The incidence was found to be of the same magnitude in men and women, while the corresponding ratio for prevalence figures was 3:1. It is suggested that men seeking sex reassignment represent a more heterogeneous group than women, and that the reported male predominance to date is due to a lack of categorical studies of primary/ genuine transsexualism. It would appear that genuine transsexualism is, on the whole, insensitive to societal changes. The fundamental disturbance underlying this psychosexual identity disorder is suggested to be neurobiological in origin.