Transsexualism is a complex concept that is very difficult to define. Many definitions have been used over the years, both by medical services and the transgender community. As with any sensitive condition, some of these terms are somewhat controversial and have attracted a number of criticisms, both from those trying to support transsexuals and among the transsexual community itself.

Transsexualism is classified as a medical condition and is described in the International Classification of Diseases, 10th Edition (ICD-10). It is described as a desire to live and be accepted as a member of the opposite sex, usually associated with a sense of discomfort with one's biological sex. For the diagnosis to be made, these features need to be be longstanding (at least 2 years) and must not be secondary to a mental illness (such as depression or schizophrenia), or be a symptom of an intersex or genetic abnormality.

There are different subgroups of Transsexualism, which reflect both the clinical differences, and perhaps also differences in terms of underlying causes.

The main ways to subdivide transsexuals is either by birth sex (Male to Female transsexuals, and Female to Male transsexuals) or by the age of onset (Primary Transsexualism or Secondary Transsexualism).

Primary transsexualism is evident from a very early age and is often associated with a lack (or very minimal) history of sexual arousal when cross-dressing, low sexual activity with a degree of gender dysphoria dating back from childhood. There has also been some suggestion that these individuals tend to display sexual interest in the same biological sex and tend to respond very well to specialist treatments (including hormone therapy and gender reassigment surgery).

Secondary transsexualism tends to present much later in life, are often male (particularly if they are sexually attracted to women) and may have engaged in a number of previous relationships, marriages and possibly had children. Many of these male individuals would initially have been identified as fetishistic transvestites (with a strong association with sexual arousal when cross-dressing). Later this can evolve into dual-role transvestitism before, over time, meeting the criteria for the diagnosis of transsexualism to be made. These types of individuals, which can be male or female, are known as Secondary transsexuals.

Many people feel uncomfortable with the medical model for Transsexualism and find the diagnosis itself controversial. There are clearly both advantages and disadvantages for this. Read more about this on the Diagnosis page. And don't forget to tell us your views on the Blog.