"Sometimes, our sciences create kinds of people that in a certain sense did not exist before ... What Sciences? ... the human sciences, which, thus understood, include many social sciences, psychology, psychiatry and, speaking loosely, a good deal of clinical medicine."Making Up People, Ian Hacking 
"Hysterical contagion," "mass hysteria," and "mass psychogenic illness" are synonyms for the form of collective behavior that consists of the dissemination of a set of symptoms for which no physical explanation can be found ..." 
1. At the beginning of the 1950's the 'kind' of persons we call transgender did not exist.
2. Gender, in the context it is both currently used and misused , had not been separated from biological sex.
3. Terminology such as 'gender identity', 'gender expression', 'gender role' and 'gender variance' were not a part of any psychological lexicon.
4. Identity had not replaced the soul as a metaphor for self.
"Today the term gender in idiomatic English and in translation, applies to human beings in such expressions as gender role, gender identity, and gender gap. Thirty years ago, however, these expressions did not exist in any language. The standard dictionaries of the time defined gender as having only a grammatical usage, namely to refer to the sex of nouns, pronouns, and adjectives, or their suffixes . . . The expansion and present popularity of the concept of gender as a human attribute dates to 1955 and to a paper, the first of a series on hermaphroditism, published in the Bulletin of the Johns Hopkins Hospital."(Money, J. 1985, The Conceptual Neutering of Gender and the Criminalization of Sex). 
In this paper Money attributes coinage of the term 'gender identity' to psychologist and homosexual rights researcher, Evelyn Hooker. 
|Evelyn Hooker 1907-1996|
Money introduced the terms 'gender role' and 'gender expression'. Together with 'identity' these have formed the key-planks in the evolution of transgenderism as a psychogenic epidemic. 
But the mere introduction of concepts and terminology is not necessarily enough to spark off a psychogenic contagion, or to create a new 'kind' of person:
"...[that process is] driven by several engines of discovery", writes Ian Hacking, "which are thought of as having to do with finding out the facts, but they are also engines for making up people. The first seven engines in the following list are designed for discovery, ordered roughly according to the times at which they became effective. The eighth is an engine of practice, the ninth of administration, and the tenth is resistance to the knowers." (Making Up People, N1 supra)
3. Create Norms!
10. Reclaim our identity!
Hacking might well have included historicise. Origin stories - insisting that a particular kind of person has 'always' been in existence: have been recognised by other cultures or at other times, and that science has really just rediscovered their existence, are a powerful and arguably necessary precursor to the other ten. All origin stories have a familiar ring.
"Evidence of multiple personality is not a new development of the twentieth century. In fact, evidence of multiple personality is said to exist in the images of shamans changed into animal forms or embodying spirits in Paleolithic cave paintings. Throughout recorded history cases of demonic possession have been reported that many experts now believe are cases of of multiple personality. Beginning in the eighteenth century, more detailed accounts in terms of multiple personality being a mental condition began appearing." 
"To defend the validity of attention-deficit hyperactivity disorder (ADHD), scientists occasionally draw on forms of evidence that have popular appeal but that are unfortunately palpably unscientific. [The] story of the origin of ADHD diagnosis is repeated in countless articles, books and web-sites and is used as evidence that the contemporary ADHD diagnosis is 'real'..." 
The ADHD story of origin reads thus:
"...the first person to describe ADD ADHD (attention deficit disorder) in its commonly accepted sense was Dr. Heinrich Hoffman ... Contrary to popular belief, this work was not a recent occurrence, but happened way back in 1845..." 
Origin stories for gender misidentification are equally common, as Richard Green demonstrated when he wrote...
"The phenomenon of lifelong, extensive cross-gender identification ... is not new, either to our culture or our time. Numerous descriptions from classical mythology, classical history, Renaissance, and nineteenth century history, plus many sources of cultural anthropology point to [its] long-standing and cultural pervasiveness..."(Richard Green, in Green,R and Money,J. 1969. Transsexualism and Sex Reassignment. Baltimore. Johns Hopkins University Press. p22)
In each case history and myth are reconstructed in order to shoe-horn superficially similar phenomena into a newer contemporary psychological paradigm. For the disorder to have a valid present it must also be given a past. Apropos transgenderism, examples of similar historical misuses are not uncommon. But to do that topic justice a separate section is required.
For now it is enough to understand that in modern and more secular cultures, the ancient, pre-existing, spiritual perspectives have been displaced, either by actual 'hard' science, or by theory presented as fact and structured to give the appearance of science.
Gender identity theory fits neatly into the latter category. It is undoubtedly that which has presented the opportunity for a raft of new identities to appear, almost literally from out of nowhere. 'Gender queer', 'agendered', 'transgendered', (itself a completely new way of identifying) and 'pangendered', to name just a few. These did not occur in other milieus simply because models premised on the existence of transmigratory male and female souls or other forms of religiosity made no allowance for them: all that could transmigrate was that which culturally speaking, was already in existence.
The new identities are almost certainly the products of Hacking's looping effect: psychologists separated sex from gender and the target group of that separation assimilated it - and changed! Identity had replaced the soul as a metaphor for self.