No, but this remains a stereotype about transgender people. Gender Identity Disorder is listed in the Diagnostic and Statistical Manual-4th Edition (DSM-IV), a guide used by mental health professionals to diagnose psychological conditions. Transgender identity is not a mental illness that can be cured with treatment.
Rather, transgender people experience a persistent and authentic difference between our assigned sex and our understanding of our own gender. For some people, this leads to emotional distress.
This pain often can be relieved by freely expressing our genders, wearing clothing we are comfortable in, and, for some, making a physical transition from one gender to another.
For people who identify as transsexual, counseling alone, without medical treatment, is often not effective. Until 1973, homosexuality was considered a mental illness; mental health professionals now know that it is part of the normal range of human sexuality.
In the same way, we believe that in the future people will recognize that gender differences are also part of the spectrum of human expression.
Being Transgender or Gay is not a choice, being Transphobic or Homophobic is, so don't be a Twonk