To sum things up, Gender Identity Disorder is a real and serious problem. Although we don't know all of what may be the cause or causes of the problem that these individuals feel toward their assigned sex, we can be reasonably certain that it is connected with either a congenital irregularity, an irregularity that occurs in the first few years of childhood or some combination of the two. We also know that every individual's sense of gender, once established, is unchangeable over the individual's life time. Men do not suddenly think they are women and women do not suddenly think they are men. This is true for transsexuals as well as those whose sense of gender does correspond to their genitalia.
Most transsexuals report being aware of their condition from the age of four to seven.
The only variable is the individual's ability to tolerate the anxiety of feeling missexed. If the individual's gender dysphoria is a relatively minor one, cross-gender lifestyle changes in periodic dressing and behaviors may be all that is necessary to ease the anxiety. However, if the individual's dysphoria is profound, a life style change may be insufficient. In this latter case, gender expression moves from a lifestyle problem to a life-threatening imperative. Bulliet, C., Venus Castina, Famous Female Impersonators Celestial and Human.