We entrust doctors with our health. Patients have the right to expect that those doctors will make decisions based on evidence-based clinical guidelines, not modish fads, grounded in the “first, do no harm” principle. That’s perhaps never more important than when it comes to life-altering medical intervention for children.

So it’s hard to make sense of a decision by the governing council of the doctors’ union, the British Medical Association, to pass a motion criticising a groundbreaking evidence review of healthcare for gender-questioning children, led by the distinguished paediatrician Hilary Cass.

It is a highly contested area of medicine, which is why NHS England commissioned an independent review in 2020. Cass published a damning final report in April, concluding that the NHS specialist gender clinic for children – now closed – put an unknown but significant number of gender-questioning children on puberty-blocking drugs and/or cross-sex hormones, undeterred by the lack of evidence of benefit and potentially very serious risks to their long-term health.

This was despite the fact that studies suggest that gender dysphoria resolves itself naturally in many children; is often associated with other underlying factors, including young people processing their own same-sex attraction, neurodiversity, childhood trauma, fear of puberty (especially in girls), and mental health issues; and that a childhood diagnosis of gender dysphoria is not predictive of a lasting trans identity in adulthood. In other words, there is a real risk that putting children on to a medical pathway could cement a temporary distress into something more permanent.

The review recommends a complete rethink of NHS services for gender-questioning children: a holistic, therapeutic-first approach, with puberty blockers prescribed for new patients only as part of an NHS research trial – recommendations that the NHS has acted on.

There’s no two ways about it: the Cass review pulled back the curtain on how gender-questioning children have been starkly failed by the medical profession. You might think that would prompt reflection. Not at the BMA: it has just announced that its governing council of 69 medics has passed a motion accusing the Cass review of making “unsubstantiated recommendations”, calling for the BMA to “publicly critique” the review and to “lobby… to oppose the implementation of its recommendations”, including halting the use of unevidenced drugs on children outside a trial. The BMA has also, ludicrously, called on the government not to implement the Cass review while it undertakes its own review. It would be one thing if the BMA had a serious critique of the review. It does not. When I asked, it could not tell me which of the Cass recommendations the council believed to be unsubstantiated, saying it would not prejudge its own review. Its press release points to two papers that are not peer reviewed or published in a reputable scientific journal – thus obliged to declare conflicts of interest – as evidence of sufficient concern about the review’s methodology to justify pausing its implementation.

The Yale Law School paper cited by the BMA was written by a mix of legal and medical academics, a majority of whom are members of the World Professional Association for Transgender Health. WPATH is a US organisation whose clinical guidelines for gender-questioning children were directly criticised by the Cass review for its lack of developmental rigour and failure to reference its own systemic review of the evidence. Evidence has since emerged suggesting that WPATH actually tried to suppress the systematic reviews that it commissioned from Johns Hopkins university because the results undermined its preferred approach, and that it was pressured by the Biden administration to remove minimum ages for treatment from its 2022 standards of care. The Cass review also found a study by at least one of the paper’s authors to be of low quality.

The second paper that the BMA cites is a preprint that takes an ideological position that evaluating these medical interventions with reference to mental health outcomes is a misguided endeavour because it “contradicts the depathologisation of transness”. One of its authors is the lead signatory of a public letter that spreads misinformation about the Cass review’s methodology that has since been comprehensively debunked.

How on earth did the BMA get itself into a position where its doctors are calling for the NHS to reinstate the prescription of unevidenced medicines to children, prompting the Academy of Royal Medical Colleges and the Association of Clinical Psychologists to put out statements in support of the review? I’ve spoken to several of its members who are absolutely furious at the lack of consultation beyond the council, elected on a turnout of just 7% of the BMA’s 160,000-strong membership, and the way this seems to have been stitched up behind closed doors, despite the consultants’ committee last year passing a motion calling on the BMA to facilitate discussion of the Cass review. One council member has gone on the record to say that she believes the BMA’s position to be out of step with its membership.

It’s not the first time that the BMA has embarrassed itself by making interventions in critical health policy issues that it doesn’t properly understand; it did the same over Covid vaccines in 2021.

It seems that the BMA leadership has been sucked into a polarised debate, characterised by a misinformation campaign by activists and academics who don’t like what the Cass review found. That campaign has included an unsuccessful judicial review of the government’s decision to ban the private prescription of puberty blockers for gender dysphoria (the high court last week ruled that the Cass review amounted to “powerful scientific evidence in support of restrictions on the supply of puberty blockers”), and false claims made about young people and suicide that the government’s adviser on suicide prevention described last month as “distressing and dangerous”.

Yes, the BMA is run by doctors. But it was clinicians who were behind this scandal in the first place. The BMA’s intervention serves as a reminder of how easily some doctors can become blinded by misinformation to the reason, rationality and evidence that are critical to the best interests of patients.

It shows that the publication of the Cass review isn’t enough. The many doctors who stand by “first, do no harm” must ensure that their colleagues return to the evidence in relation to this group of vulnerable children who deserve so much better from the medical profession.