Because gender identity disorder is currently considered a psychological disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), a mental health professional such as a psychiatrist, psychologist or therapist must make the diagnosis.
The World Professional Association for Transgender Health (WPATH), formerly known as the Harry Benjamin International Gender Dysphoria Association, maintains and publishes the Standards of Care (SOC) -- guidelines for how to treat people with gender identity disorder. The Standards of Care are intended for professionals, individuals with gender identity disorder and their families, as well as institutions or anyone else seeking to understand current information about the psychological, medical and surgical treatments for GID.
In accordance with the Standards of Care, when an individual begins to question and feel persistent dissatisfaction with his or her gender identity, no matter at what age, therapy -- psychological, endocrine or surgical -- should begin. Treatment is intended to help the patient's well-being, not to sway or convince a person from his or her path.
Gender identity struggles may begin as early as age two to four years, when children begin to exhibit interest in cross-gender activities.
Most will outgrow symptoms of gender identity disorder before adolescence. By late adolescence or adulthood, about three quarters of boys with symptoms of gender identity disorder report homosexual or bisexual orientations. Most of the remaining 25 percent live as heterosexuals [source: Merck]. A small percentage of adolescents and adults will go on to identify as transsexuals.
Adult gender identity disorder typically manifests in late adolescence or in early to mid-adulthood, although there is no determinant age of onset. Adolescents questioning their gender identity usually report cross-gendered feelings since childhood. Later onset gender identity disorder usually appears gradually, with individuals seeking therapy in early to mid-adulthood.
Next we'll talk about the specifics -- what are the symptoms and criteria for diagnosis?