Puberty blockers: what are they and why are they in the news?

Until recently, discussions about specialist hormone treatments for blocking puberty were mostly limited to medical professionals, a small number of young patients and their families. Now they are the subject of heated public debate in the UK after the outgoing Conservative government rushed through an “emergency ban” on such treatments as one of its final acts.

With Labour’s new health secretary, Wes Streeting, preparing to make that ban permanent, our Trans+ Voices project breaks down what it could mean for young trans and non-binary people in the UK – and what might happen next.

What are puberty blockers?

Drugs known as puberty blockers do exactly what their name suggests: they suppress the production of hormones associated with puberty, in turn delaying the changes that come with it – like growing breasts or facial hair, starting menstruation, or voices breaking – which can be distressing for young people who are trans or questioning their gender.

Like all medical treatments available in the UK, puberty blockers have been tested and meet strict safety and quality standards. Multiple studies have found that their effects are temporary and reversible following short-term use, though some have suggested more research is needed into their long-term effects. Young people unsure about their gender sometimes take them temporarily, to “pause” puberty and give themselves more time to decide how they feel.

Testing has particularly focused on young people who are cis (meaning they identify with the sex they were assigned at birth) but who experience puberty too early – sometimes known as “precocious puberty”. There has been less research carried out specifically with gender-questioning young people, which has led some critics to describe the use of puberty blockers in these situations as “experimental”. However, a 2020 study concluded they were no more experimental than any treatment given to children for other reasons.

Studies have also found that access to puberty blockers for trans young people can reduce their risk of suicide, depression and self-harm.

In March 2024, the BBC reported that fewer than 100 under-18s in England were currently prescribed puberty blockers by the NHS.

How did we get here?

In 2020, paediatrician Dr Hilary Cass was asked by NHS England to carry out a review into healthcare for trans young people.

Cass’s interim report was published in February 2022. It included guidance on how to safely and ethically prescribe puberty blockers, but also said it was not able to provide definitive advice on their use “due to gaps in the evidence base”.

NHS England responded by banning new puberty blocker prescriptions for gender-questioning young people – but not for cis people experiencing precocious puberty – in March 2024. Scotland and Wales did the same in the months afterwards. Northern Ireland has not prescribed puberty blockers to under-18s since 2020.

The final report of the Cass Review, published in April 2024, did not find that puberty blockers were unsafe or recommend that they should be banned. Following an in-person Q&A with Dr Cass, LGBTQ+ charity The Kite Trust summarised her position.

“The Cass Review Report recommends that a different approach is needed, with puberty-suppressing hormones and gender-affirming hormones being available to young people at different ages and developmental stages alongside a wider range of gender-affirming healthcare based on individual need,” they wrote.

Shortly before May’s election, the Conservative government announced the “emergency” three-month ban on all private prescriptions, in a bid to “close loopholes”. The trans advocacy organisation TransActual UK, in partnership with the not-for-profit Good Law Project, mounted a legal challenge, alleging that the use of emergency processes was unlawful and the consultation process “partial and unfair”.

What did Wes Streeting say?

The 2024 Labour party manifesto pledged to implement the recommendations of the Cass Review, despite criticisms from LGBTQ+ organisations and academics who said the methodology was flawed and its conclusions unsupported.

Earlier this month, Streeting said that he intended to go even further than the recommendations by making the ban permanent. He defended his position on X, writing that puberty blockers had been extensively tested and proven safe for use by children who start puberty too early, but that “this is different to stopping the normal surge of hormones that occur in puberty”.

“We don’t yet know the risks of stopping pubertal hormones at this critical life stage. That is the basis upon which I am making decisions. I am treading cautiously in this area because the safety of children must come first,” he wrote.

“The decisions I am taking will always be based on evidence, rather than politics or political pressure.”

What has the response been?

While Streeting’s announcement was endorsed by so-called “gender critical” campaigners such as JK Rowling and fellow Labour MP Rosie Duffield, it was criticised by LGBT+ campaigners and a number of his other parliamentary colleagues.

Susie Green, former CEO of trans youth Mermaids, said the ban was “dangerous and a complete disgrace” while Nancy Kelley, former chief executive of LGBTQ+ charity Stonewall, said: “The ‘risk’ that stalks [this] debate… is the ‘risk’ a trans child will grow up to be a trans adult. If you believe (as I do) that being trans is a naturally occurring part of human diversity, the picture looks very different.”

Clive Lewis is one of a number of Labour MPs who have opposed the prospect of a permanent ban, writing on X: “A blanket ban is wrong & not what Cass recommended. Careful, clinical provision is the way forward, not this politicisation.”

What comes next?

TransActual’s legal case concerning the original emergency ban was dismissed at the High Court today as the judge ruled the ban lawful.

An open letter by Labour for Trans Rights earlier called for Streeting to withdraw support for the ban and gathered more than 3,000 signatures; the group has now prepared a motion for local activists to bring to their own constituency Labour party or branch meetings.

LGBT+ Labour has also written to Streeting outlining concerns and calling for him to urgently announce the timeline and scope of a clinical trial for puberty blockers. At the time of writing, Streeting has yet to publicly respond to the letter.