As doctors and nurses prepared to undertake gender reassignment surgery, their patient was almost overwhelmed with anxiety and emotion.

''I'd been wanting it so much for such a long time, but when the moment actually came I wasn't sure whether I could do it,'' Norrie says, sitting happily in a Redfern cafe. ''I kept thinking, 'am I about to jump out of this bed?'''

The surgery went ahead and Norrie's penis was removed. For a while, with the assistance of powerful hormone pills, he became a she and things seemed to be right in the world. But the sense of fulfilment didn't last.

''After the surgery I felt like a woman but people didn't feel like I was a woman,'' Norrie says. ''I thought - 'this is so unfair, I played by the rules but the rules aren't being stuck to'.''

Experiencing a growing sense of confusion about her identity, Norrie stopped taking hormones and began delving into the rapidly growing body of work examining the concept of gender identity.

It was there Norrie discovered Anne Fausto-Sterling's seminal paper The Five Sexes.

''That really turned the light on,'' Norrie says. ''I could step out of the idea that you're male or female … I said 'what would I want to be? And the answer was a hermaphrodite.'

''I decided that if people are being born hermaphrodite then it's obviously part of the way things are. I didn't want to be stuck in one box when I could be doing things that are ascribed to the other.''

Norrie began to embrace the concept of being neither male nor female. ''Hoodlums take great pleasure in yelling out ''trannie!'' and I began to take great pleasure in yelling out 'well spotted!'''

Inspired by others who had fought for the right to be registered as neither male nor female, Norrie began pushing for recognition, firstly on a passport and then later on basic documents with the registrar, seeking a ''non-specific'' designation rather than the obligatory ''M'' or ''F''.

Then, gender diversity campaigner Dr Tracie O'Keefe rang Norrie and suggested an application for a ''non-specific'' gender designation with the NSW Registrar of Births Deaths and Marriages. ''We wanted a test case,'' Norrie said.

After initially granting Norrie the ''non-specific'' designation in 2010, the NSW registrar suddenly reversed his decision. ''I was gutted when they took the certificate back,'' Norrie says. ''We'd gone on the front page of the SMH and suddenly they reversed the decision and I couldn't see a way out. I thought I'd given it my best shot and failed.

''But Tracie said 'no, there are options - we can fight this'.''

Two subsequent legal challenges by Norrie were unsuccessful. But in May last year, represented pro bono by Sydney law firm DLA Piper, a third challenge was successful in the NSW Court of Appeal. But this was, in turn, challenged by the registrar in the High Court.

Counsel for the registrar argued that the acceptance of more than two categories of sex would cause ''unacceptable confusion''. But the five-judge panel rejected this argument.

''For the most part, the sex of the individuals concerned is irrelevant to legal relations,'' their judgment says.

The judges said the Commonwealth Marriage Act was ''the chief, perhaps the only, case where the sex of the parties to the relationship is legally significant''.

They found there was ''evident force'' in the argument that to classify Norrie as male or female while her sex remained ambiguous would be to record misinformation in the registry.

The sense of recognition and vindication for Norrie was enormous, but the decision also has major ramifications for individuals and institutions across the country.

''It will be binding on those states such as Victoria and Queensland, that have identical or similar legislation,'' Norrie's solicitor, Scott McDonald, from DLA Piper, said.

''On the ones that don't it will be persuasive authority - they will get the guiding principle and understand what the High Court is trying to achieve.

''And if they try to legislate their way around it that they will probably get themselves in trouble, so in terms of sending a message that sex isn't binary I think that's a message that can be felt through states' legislation no matter what it is.''

While the Norrie decision relates specifically to people, such as Norrie, who have had gender reassignment surgery, it also has implications for gender diverse people more broadly.

Babies born in NSW with ambiguous gender characteristics must currently be listed as either male or female on their birth certificates. Some believe this encourages parents to hurriedly pick a sex for their child, or, more worryingly, rush into surgical procedures for their baby to ''fix the problem''.

It is now likely the ''non-specific'' designation can also be used in these circumstances, removing some of the pressure to confirm to the male-female binary distinction .

''Doctors, when a child is born, do actually assign a gender to the child even if they're a mix of female and male and that reflects our social norms and legal frameworks,'' says Anna Brown, a lawyer from the Human Rights Law Centre, who specialises in gender diversity.

''Until we change the law and change our institutions it really does inhibit the free expression of these identities. Doctors will keep assigning genders and ordering surgeries until society accepts gender diversity and we have laws which encourage that.''

But the past two years have seen what Brown describes as a ''quiet revolution'' in terms of the legal recognition of gender-diverse and intersex people, and Australia has been at the forefront.

One of the last acts of the Rudd-Gillard government was to amend the Sex Discrimination Act to specifically prohibit discrimination against intersex people.

Not long after, it introduced guidelines for all federal government departments discouraging them from using ''male'' or ''female'' on their forms, or, when this was unavoidable, including a ''non-specific'' option.

Earlier this year the ACT amended its births deaths and marriages laws so that people can change their designation on their birth certificate after undergoing gender reassignment treatment that does not need to consist of surgery.

It follows the lead of countries such as Germany, which have introduced similar legislation.

''What we've seen over the last two years is a little bit exciting in terms of achieving equality before the law for gender diverse and intersex people,'' Anna Brown says.

''The developments in relation to birth certificates and similar documents are the foundations of that equality. The law is evolving to catch up with social reality and Australia is leading the change in this area. And now we have had a decision from the High Court which is the first of its kind. It's a step towards the ultimate goal of treating gender diverse and intersex people with dignity and respect.

Norrie now intends to take on the laws preventing same-sex marriage.

On the night of the High Court's decision an old friend proposed, presenting Norrie with a ring made on a 3D printer.

''As soon as my certificate comes through from the registrar, I'm heading right back there to get married,'' Norrie says.

It seems Norrie's dance with destiny hasn't finished just yet.

smh.com.au