Frequency figures for transsexualism, concerning incidence, prevalence
and sex ratio calculated in the 1960s and 1970s, were compared with r
ecent reports. The incidence figures remained constant over time, wher
eas 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 heterogen
eous group than women, and that the reported male predominance to date
is due to a lack of categorical studies of primary/genuine transsexua
lism. It would appear that genuine transsexualism is, on the whole, in
sensitive to societal changes. The fundamental disturbance underlying
this psychosexual identity disorder is suggested to be neurobiological
in origin.