The Metamorphoses Greek myth includes a story about a woman raised as a male falling in love with another woman,and being transformed into a man prior to a wedding ceremony and staying with her. It is therefore considered that people who desire to live as though they have the opposite gender have existed since ancient times.
 People who express a sense of discomfort with their anatomical sex and related roles have been reported in the medical literature since the middle of the ¹⁹ century. However, homosexual, fetishism, gender identity disorder, and associated conditions were mixed together and regarded as types of sexual perversion that were considered ethically objectionable until the 1950s. The first performance of sex-reassignment surgery in 1952 attracted considerable attention,and the sexologist Harry Benjamin reported a case of‘a woman kept in the body of a man’, which was called transsexualism. John William Money studied the sexual consciousness about disorders of sex development and advocated the concept of gender in 1957. Thereafter the disparity between anatomical sex and gender identity was referred to as the psychopathological condition of gender identity disorder,and this was used for its diagnostic name when it was introduced into DSM-III in 1980.
 However, gender identity disorder encompasses a spectrum of conditions, and DSM-III-R categorized it into three types : transsexualism, nontranssexualism, and not otherwise specified. The first two types were subsequently combined and standardized into the official diagnostic name of ‘gender identity disorder’in DSM-IV. In contrast, gender identity disorder was categorized into four groups（including transsexualism and dual-role transvestism）in ICD-10.
 A draft proposal of DSM-5 has been submitted, in which the diagnostic name of gender identity disorder has been changed to gender dysphoria. Also, it refers to ‘assigned gender’rather than to ‘sex’, and includes disorders of sexual development. Moreover, the subclassifications regarding sexual orientation have been deleted. The proposed DSM-5 reflects an attempt to include only a medical designation of people who have suffered due to the gender disparity,thereby respecting the concept of transgender in accepting the diversity of the role of gender. This indicates that transgender issues are now at a turning point.