In 1954 an American doctor, Harry Benjamin (described as the “pioneer of transsexual research”), first introduced the term “gender role disorientation” to label biological males or females who were convinced they were really members of the opposite sex, but had been endowed with the “wrong” set of genitals. It’s difficult to estimate the extent of transsexualism because only a small percentage of transsexuals seek medical help. The ratio of male to female is about three or four to one. Reasons for this ratio are unclear but it might be that a woman dressed as a man is less conspicuous and more acceptable than a man in a skirt. Despite the lack of accurate statistics, it is safe to say that transsexualism affects only a minute proportion of the population. (A 1968 estimate for the USA suggested there was only one male transsexual to every 100,000 people.) But transsexualism does raise two potentially hazardous problems for the doctor, patient, and society: how should the condition be defined and how can transsexuals be helped?