Gender Identity Disorder (GID) has been attracting social attention in Japan since 1998, when Sex Reassignment Surgery (SRS) was officially approved by Saitama Medical School. It may occur that the number of GID patients will increase. However, many Japanese GID patients are still distressed by the hostility and misunderstandings. Many GID patients have experiences of school refusal, suicidal ideation, or other psychiatric illnesses. Taking these distresses into account, more psychological and social supports for GID patients are necessary in order for them to live with satisfaction. In the paper, we would like to introduce current psychological studies both in Japan and in the world, most of which were written in the 21st century and some of which referred to ”transgender.” Examining these studies, it appears that psychologists and psychotherapists will have to explore more (1) psychological and social support for students with GID in school, (2) psychological change after SRS, (3) psychological interventions for couples when the other confesses his or her GID, (4) psychological change in real life experience and psychological support for GID patients, and (5) studies on mental health of aging GID patients.