The British Medical Association (BMA) has called for the ban on puberty blockers for under-18s to be lifted.
The doctors’ union also wants a pause on the implementation of a landmark review into gender care for children and young people.
It said it wanted to undertake an evaluation of the Cass Review after academics expressed concern about its approach.
The review, commissioned by NHS England, called for a move away from medical interventions for children struggling with their gender identity and advocated a more holistic model incorporating better mental health support.
It took four years to carry out and was widely welcomed by the medical establishment in the UK.
The review was led by leading paediatrician Dr Hilary Cass and prompted the last government to ban the use of puberty blockers for under-18s questioning their gender – a move which was then supported by Labour when they won the election.
These drugs suppress the natural production of hormones and delay the onset of puberty.
The ban applied to private clinics, because the NHS had already stopped using them outside of clinical trials, and was challenged in the High Court by campaign group TransActual.
But a judge ruled earlier this week that the ban was lawful.
The BMA said members of its Council, its top decision-making body, voted in favour of a motion last month that was critical of the Cass Review and called on the union to “publicly critique” it.
The BMA said it was concerned about its impact on transgender healthcare provision because of its “unsubstantiated recommendations”.
It pointed to one piece of research published online earlier this year as a sign that academics were concerned about the way the Cass Review was carried out.
BMA leader Prof Philip Banfield said: “This is a highly specialised area of healthcare and as doctors we want to be sure they get the most appropriate care and support they need.”
It said it expected its evaluation to be finished by the end of the year – and said it wanted to see a pause on the implementation of the Cass Review recommendations in the meantime.
The BBC has approached the Cass Review for comment.
A Department of Health and Social Care spokesperson said: “The Cass Review is a robust report backed by clinicians and firmly grounded in evidence.
“NHS England will be implementing Dr Cass’s recommendations so that children and young people get the safe, holistic care and support they need. We do not support a delay to vital improvements from the NHS to gender services.”
