From Illusion to Reality... 

Living in the role of the opposite sex has been a practice of mankind for centuries. In the seventeenth and eighteenth century it was not uncommon to find women who joined the army or served as sailors, pretending to be male.  Also, men have historically dressed and behaved as women. Famous among these were the Roman emperor Calligula, King James I of England, Governor of New York Lord Cornbury, etc.. However, in all these cases, gender dysphoric behavior was episodic.  We would now probably label them as transvestites (those who wear the clothing and demonstrate the mannerisms of the opposite sex). 

The story of Chavalier D'Eon, a nobleman who served the French King Louis XV as a diplomat in Russia is better known.  The year before his appointment, he spent several months in disguise, presenting himself at the Russian court as his own non-existent sister Lea. He became very popular as a woman and no one ever doubted his self-assigned sex. Later, he served in England where rumor had it that he was in fact a female. He refused to settle the question. On the royal order of Louis XV he was obliged to dress as a woman & live a female role until his death in 1810.  The autopsy showed that he had the body of a normal male, much to the chagrin of the public and the people who knew him closely. 
 

Much as it might have been desired by those who lived previous to the last century, hormonal and surgical gender reassignment were impossible until the 1930s.  Modern documented history of transsexualism and gender reassignment starts at that time with the first recorded sex change operation on a Danish artist in Germany.  Einar Wegener became Lily Elbe. 
 

It was only in 1953 with the story of the surgical gender reassignment of the American ex-GI George Jorgensen, who became Christine Jorgensen, that transsexualism received worldwide publicity.  In fact, a movie of her life was produced by Hollywood and her autobiography still sells quite well.

Transgenderism is seen all over the world. However, its expression varies from one culture to another.

In Oman, men who live as females are known as "xaniths." Their place in society is literally between that of men and women. They retain male names, wear clothing which is partly male and partly female and cut their hair to a medium length. Unlike other men, they have the right to socialize with women. Conversely, unlike women, they also have the right to move unescorted in public. They also may live alone,  be hired as house servants, and work as prostitutes in a culture where prostitution is otherwise prohibited.
  

Another cultural variant of cross-gender behavior is seen among some American Indian tribes. A young adolescent boy displaying effeminate traits is known as a "berdache."  After getting into a divine trance and receiving 'spiritual enlightenment,' a berdache begins to dress as a female and engages in sexual relations with males or even lives as a berdache wife with a husband. 

In India we have the "hijra" community which is a motley group of people belonging to various religious communities. Many of them are male-to-female transsexuals but the group also consists of adolescent boys who have undergone early castration and children with intersexual traits.

Traditionally, all hijras undergo amputation of the penis, scrotum and testis.  This is a very crude procedure performed by established senior hijras. The hijras form a kind of a social institution--a religious cult with its own mother goddess, Bahuchara Mata. 
 

Similarly, male-to-female transsexuals in Burma group together. They are looked upon as being possessed by the spirit of the opposite sex. They play a special role in temples and are known to participate in special religious ceremonies.
-
From Country to Country...
The exact prevalence of transgenderism is difficult to assess because only a fraction (size being dependent on the socio-cultural ethos) of those who practice this lifestyle seek therapy.  However, in the USA, it is estimated at 1 in 100,000 for male-to-female transsexuals and 1 in 400,000 for female-to-male transsexuals. In England, 1 in 30,000 and 1 in 100,000. In Sweden, 1 in 37,000 and 1 in 103,000. The ratio of male-to-female and female-to-male remains around 3 to 1 regardless of the country.

Most adult transsexuals confess to having experienced a hatred for their gender long before puberty.  Many remember puberty with abhorrence because of the hormone-induced changes in body characteristics which they perceived as totally alien to their gender identity. Furthermore, it is during this time that most of those who experience dissatisfaction with their natural sexual identity choose to make the change.

In some cases, a disdain for one's gender is seen at a very early age. For example, it may manifest itself in a young boy as a desire to wear little girl clothing and to play with dolls. Retrospective studies have corroborated that such boys often grow up to be either homosexuals or transsexuals.

What this means is that those who believe themselves to be transgendered have been among us all throughout the history of our species.  It does not mean that being transgendered or transsexual is a naturally occurring event.