Gender Identity Disorder (GID) has been recognised for at least 25 years as a "genuine psychiatric medical condition" which is irreversible and incurable, Mr Justice McKechnie said. An estimated one in 10,000-12,000 males and one in 30,000 females are affected.
For those who portray any characteristics other than those associated with their biological sex, the condition can cause great humiliation, ridicule, isolation and outright discrimination, he said. "It is on any treatment of the subject a most serious condition." He had found Dr Foy "utterly genuine, honourable and committed" and accepted her repeatedly expressed conviction of having no choice in her search for treatment.
In a detailed analysis of sexual differentiation, transsexualism and GID, the judge said GID, formerly Gender Dysphoria to include Transsexualism, is now the term preferred by professionals to describe those who suffer from the condition of Dr Foy.
At its most simple, GID consisted of a person having a persistent dislike and discomfort for their own outward looking sex and a feeling that such sex was quite inappropriate to their inner selves. There was no suggestion GID was congenital in origin.
Those with GID had intense feelings of rejection for their behaviour, attributes, attire and stereotype expectations of their biological sex and had a pervasive desire to be, to belong to, to live and to be accepted as a member of their opposite sex. Many were prepared to undergo a variety of treatments to achieve, for that purpose, the desired level of compatibility with the gender of choice.
In short, the judge said, such people had an innate belief that they lived in the wrong body, either in whole or in part and that, for their inner self-fulfilment, it was necessary to discard the role expected of them in their biological gender and be transformed into, adopt and pursue the role expected of the opposite sex.
"They believe, truly and rationally, that they are members of that sex," he said. "This condition is indiscriminate as to creed, class, profession, calling or social position. It can affect virtually all age groups from the very young to adults in their sixties."
He said the condition was irreversible with no cure, although acceptance of one's altered position could be achieved by stopping at different levels of the treatment sequence available. The condition manifested itself in varying degrees of severity and widespread and substantially differing symptoms including feelings of being and belonging to the opposite sex, cross-dressing and an abhorrence of male or female stereotypical activities including the co-use of lavatories and showers.
The reaction to and manner of dealing with the condition also varied greatly. Some suppressed it in whole or in part and conformed to role and expectation. Others, who were born male, adopted increasingly masculine roles and many totally over-compensated in that way. Some satisfied their condition by cross-dressing at safe times, while others married to protect their image.
However, for some treatment was essential. Some had hormonal treatment while others felt they had to have surgery. For virtually all with GID the condition was distressing, he said. Without treatment, the reported suicide rate was "not insignificant".
The judge outlined the standards and conditions which must be met before certain treatments, including hormonal treatment, may be embarked upon. He said the foremost expert in Ireland on GID is Dr Frank O'Donoghue, a consultant psychiatrist attached to St Patrick's Hospital, Dublin. Dr O'Donoghue had seen between 30-40 people in the past 25 years whom he would have diagnosed as having GID. Of that number, about half would have been recommended for surgery. There was no surgery available in Ireland.
The judge referred to certain studies which argued there is a neurological explanation for the condition of transsexualism. He said there were "several limitations" with those studies.