We now have two major cases in which civil and criminal courts have sent the law in this country on a path that has a great deal in common with the fable of the Emperor’s New Clothes.

The law, as explained by the courts, is asking people to deny the evidence of their own eyes and accept that men can do much more than change their gender identity – they can actually become women.

In the fable by Hans Christian Andersen, a naked emperor was reduced to a laughing stock for walking naked in the street while believing he was clothed in finery.

That fate, and worse, is awaiting Australian justice unless the nation’s parliaments move quickly to protect the credibility of the courts.

The justice system can do many wonderful things. It can end discrimination against vulnerable people, punish wrongdoers and protect our rights and liberties.

It does that by applying the law to the facts, regardless of the beliefs of the parties.

But when courts feel compelled to deny biological reality – which is now happening in Australia – it strikes at the core of the judicial function – the application of law to facts.

We are witnessing the beginnings of a different system – one in which the law is applied not to the biological facts, but to the beliefs of men who honestly consider themselves to be women.

These men need to be treated with compassion and should be protected from discrimination.

But they remain men. If the law denies this reality, and bases decisions on beliefs, not facts, perverse outcomes are inevitable.

We are witnessing the results. It started with Tickle v Giggle – a civil case about access to a female-only app. The Federal Court’s Justice Robert Bromwich ruled last year that “sex is changeable”.

That belief also explains why vulnerable women in a Victorian prison are now housed with men who believe they are women.

One of those inmates abused his five-year old daughter, pleaded guilty and received a dramatically reduced sentence. The Victorian County Court accepted he was a woman who had been coerced by a man.

The online attention of an American sex offender had “validated you as a woman and a sexual person”, said judge Nola Karapanagioditis in sentencing remarks on August 26 last year.

In both those cases the legitimacy of the outcome – and therefore the law itself – has been rejected by significant parts of the community.

This should come as no surprise. It is the direct consequence of the failure of federal parliament to clearly deal with this issue when it changed the Sex Discrimination Act twelve years ago.

In last year’s Tickle v Giggle decision – which is subject to appeal – Justice Bromwich said parliament’s decision to repeal the definitions of “man” and “woman” in that Act pointed forcefully to sex being changeable.

If federal Labor and the Coalition parties understood this was what they were doing, they kept it to themselves.

If parliament knew it was approving a law in 2013 that would force the community to treat certain men as if they are women, this should have required explicit references in the key documents before parliament.

But as outlined in this space in July, there is no such reference in the second reading speeches of Mark Dreyfus, who was Attorney-General at the time, or George Brandis, who was shadow Attorney-General.

Nor is there any mention of such a radical legislative purpose in the explanatory memorandum that accompanied the removal of those definitions.

So here’s where we stand: the law as applied by the Federal Court and the County Court of Victoria now accepts that men can be women.

The key documents before parliament in 2013 made no such claim yet have been interpreted by Justice Bromwich as requiring him to rule that a man can become a woman.

The lesson? Vague statutes are the bane of the rule of law.

Regardless of the outcome of the appeal in that case, this entire issue should have been thrashed out and determined with great clarity when it was before parliament.

By enacting a law in which a key issue was left open to interpretation, parliament might have dodged a contentious issue. But it failed the nation.

Six years ago Jonathan Sumption, a former judge of the UK Supreme Court, argued in a series of lectures for the BBC that the judicial resolution of policy issues undermines the single greatest advantage of the political process – its ability to accommodate divergent interests and opinions.

He accepted that politics was not performing that function well “but judges will never be able to perform it”.

In Australian terms, parliament – not the judiciary – is best placed to craft a way out of this mess.

The solution needs to accommodate the legitimate interests of men who honestly believe they are women, while protecting the integrity of the justice system.

Before state and federal parliaments attack this issue, they should keep in mind that justice is the rigorous application of law to facts as they are, not as lawmakers might wish them to be.

It is entirely appropriate for transgender men to be protected from discrimination. But it’s now clear that any attempt to enact a law to transform men into women will result in injustice.

Without legislative intervention, the divergence between the law and reality will continue, endangering the vulnerable, helping wrongdoers and eroding confidence in the statutes enacted by parliament and the decisions made by the courts.