Campaigners have expressed their disappointment after the Court of Appeal overturned a previous ruling restricting the use of puberty blockers for under-16s.
Tavistock and Portman NHS foundation trust successfully challenged the earlier verdict in the case brought by Keira Bell last year.
Bell was 16 when she was prescribed puberty blockers by the Tavistock clinic before later deciding to revert back to female. She says doctors should have challenged her more over her desire for a medical transition.
In the original case, Bell, now 24, argued that it was not possible for minors to give informed consent to puberty blockers.
The High Court agreed and ruled last year that it was unlikely under-16s would be able to understand "the immediate and long-term consequences" of taking such treatment in order to give informed consent. In certain cases, the judgment said the courts should be consulted before puberty blockers could be prescribed to minors.
This judgment was challenged by Tavistock and on Friday, lord chief justice Lord Burnett, Sir Geoffrey Vos and Lady Justice King overturned it, arguing that the High Court's intervention was "inappropriate".
"The effect of the guidance was to require applications to the court in circumstances where the divisional court (a branch of the high court) itself had recognised that there was no legal obligation to do so. It placed patients, parents and clinicians in a very difficult position," the judges said.
"In practice the guidance would have the effect of denying treatment in many circumstances for want of resources to make such an application coupled with inevitable delay through court involvement."
Responding to the outcome, Bell said she was disappointed and intends to appeal to the Supreme Court.
Campaign groups critical of the use of puberty blockers by minors have also voiced their disappointment.
Transgender Trend said: "Keira Bell was 'affirmed' as a boy at the Tavistock GIDS, with no exploration of underlying factors which may have led to her gender dysphoria.
"Thus the 'affirmative care' model in itself withholds from the child the very information they need in order to give informed consent; providing only a pre-assumed certainty about the individual child's motivation and self-understanding and precluding alternative interpretations which may be useful for the child.
"Any future treatment should be centred around the developmental phases of children. It must be based upon evidence and there is no reason to revert to experimental treatments. Practitioners and clinics should reflect on the ruling of the original judges in the Bell case, even though the Court of Appeal has rejected the requirement for court intervention to sanction medical intervention.
"The key intervention must become evidence based therapeutic approaches. Only when it is evidence, rather than ideology, that underpins practice, can we honestly say our approach to treatment of gender dysphoria is driven by the premise 'first, do no harm'."
Our Duty, a parent-led group challenging gender ideology, said: "We are disappointed with today's Court of Appeal ruling. Our feelings are best conveyed in the words of Keira Bell: 'It is a fantasy and deeply concerning that any doctor could believe a 10-year-old could consent to the loss of their fertility.' Indeed, could any adolescent?"