Norrie, from Redfern in Sydney, became the very first individual granted the right to have a neutral gender.

"Today the High Court unanimously held that the Births, Deaths and Marriages Registration Act1995 (NSW) permits the Registrar to register that a person's sex is "non-specific"," a statement from High court of Australia said.

The High Court ruled that the The Births, Deaths and Marriages Registration Act 1995(NSW) allows a person to be neither male nor female. Hence, an individual may register sex as "non-specific."

"The Births, Deaths and Marriages Registration Act 1995(NSW) ("the Act") expressly recognises that a person's sex may be ambiguous. It also recognises that a person's sex may be sufficiently important to the individual concerned to warrant that person undergoing a sex affirmation procedure to assist that person 'to be considered to be a member of the opposite sex," the court said in its final ruling.

Back in 2010, Norrie registered "sex not specified" in NSW. However, four months after the registration, the registry informed Norrie that there had been "issued in error" and therefore Norrie's registration was nullified.

In an interview with Fairfax back in 2013, Norrie said that the nullification posed no problem. But Norrie was motivated to lodge a case against the nullification when people knowledgeable of the law said that the nullification was baseless.

Norrie then took the case to the Administrative Appeals Tribunal which later dismissed the case.

Norrie appealed the case to the NSW Court of Appeal where a unanimous ruling said that "as a matter of construction ... the word sex does not bear a binary meaning of 'male' or 'female'."

The Registry of Births Deaths and Marriages deemed the decision incorrect and appealed to the High Court of Australia.

The Registry argued that neutral gender sets unacceptable confusion in relation to legal relations..

However, High Court Judges said that in actuality, "the the sex of the individuals concerned is irrelevant to legal relations." In fact, sex of the parties involved is only legally significant when the Commonwealth Marriage Act is involved.

The judges agreed that if Norrie is to be classified as male or female then this is misinformation.

And while the court agreed that that male and female can only be the "registrable classes", it does not mean that "the Act requires that this classification can apply, or is to be applied to everyone. And there is nothing in the Act which suggests that the Registrar is entitled, much less duty-bound, to register the classification of a person's sex inaccurately as male or female having regard to the information which the Act requires to be provided by the applicant," the ruling said.

"The Act does not require that people who, having undergone a sex affirmation procedure, remain of indeterminate sex - that is, neither male nor female - must be registered, inaccurately, as one or the other. The Act itself recognises that a person may be other than male or female and therefore may be taken to permit the registration sought, as 'non-specific'," the judges upheld.