Transsexualism was long regarded by the medical profession as a mental disorder. Historically, denial, aversion therapies, hormone 'reinforcement' and even electroconvulsive shock treatments were the lot of those compelled to articulate their overwhelming need to identify as members of the gender opposite that assigned to them at birth. We now know and understand that, just as the gonads, genitals and chromosomes are differentiated as to gender, so too is the brain. While the relationship between brain morphology and 'gender identity' is yet to be finally proven beyond scientific doubt, the extent of empirical and anecdotal evidence supporting it continues to grow such that the factors to be considered when determining the legal gender of a person now include the person's self perception and any biological features of the person's brain that are associated with a particular gender.