The new NHS puberty blockers trial raises severe concerns. Scientifically, morally and ethically.
The NHS’s decision to proceed with a £10.7 million clinical trial on puberty blockers for children with gender dysphoria raises profound ethical, medical, and psychological concerns. The Cass Review has already highlighted the lack of robust evidence supporting these treatments, and yet, instead of taking a precautionary approach, the NHS is pressing ahead with a study that could place vulnerable children at serious risk.
This trial is not about science in its purest form—it is about salvaging a practice that has already been called into question by extensive research. While proponents argue that puberty blockers provide children with “breathing space” to explore their identity, a growing body of evidence suggests otherwise. Medical and psychological research has consistently shown that puberty blockers can impair cognitive development, cause permanent physical changes, and lead to a near-inevitable pathway to cross-sex hormones.
With no clear understanding of the long-term consequences, the question we must ask is: why are we conducting an experiment on children when the risks are already clear?
The Problem With Puberty Blockers: What the Science Tells Us
Puberty is a critical developmental stage, not just for physical changes, but for brain maturation, bone density, emotional regulation, and long-term well-being. Interrupting this process is not a neutral decision—it has consequences.
Impact on Brain Development
Research in developmental neuroscience has demonstrated that puberty plays a vital role in shaping the brain’s ability to regulate emotions, make decisions, and develop abstract thinking skills. Studies in animal models and human adolescents suggest that disrupting hormonal puberty may interfere with these processes in ways we do not yet fully understand.
One of the few human studies available, conducted in the Netherlands, found that adolescents who took puberty blockers exhibited lower IQ scores and reduced executive functioning. Another study suggested that blocking puberty could alter the trajectory of adolescent brain development, particularly in regions responsible for memory, impulse control, and emotional regulation. These concerns align with well-established findings in neurodevelopment that show hormonal puberty is essential for refining cognitive abilities and social processing.
If we know that puberty plays a fundamental role in brain development, how can we justify deliberately halting it in children whose brains are still forming?
Bone Density Loss and Long-Term Physical Consequences
One of the most well-documented side effects of puberty blockers is significant bone density loss. Research shows that children who take puberty blockers experience much lower bone mineral density than their peers, putting them at an increased risk of osteoporosis and fractures in adulthood.
A recent study found that even after discontinuing puberty blockers, some individuals never fully regain normal bone density levels, raising concerns about lifelong skeletal issues. Given that childhood and adolescence are critical periods for bone mass development, interrupting this process could lead to permanent fragility.
Despite these well-known risks, this trial proposes to subject children to a medical intervention that has been repeatedly shown to weaken their bones, without clear evidence that it provides psychological benefits.
The Psychological Impact: Are We Ignoring Underlying Distress?
Children who experience gender dysphoria are often struggling with complex mental health conditions, including anxiety, depression, trauma, and neurodevelopmental differences such as autism.
A key concern in the current gender-affirming model is that these underlying psychological conditions are not being properly explored before children are placed on a medical pathway.
- Studies show that up to 50% of children referred for gender dysphoria have autism, a significant overrepresentation compared to the general population.
- Many of these young people struggle with rigid thinking, difficulty with identity formation, and social challenges, making them particularly vulnerable to over-identification with gender as the source of their distress.
- Research also indicates that gender dysphoria often resolves naturally during adolescence if children are given time and therapeutic support rather than immediate medical intervention.
If gender distress in childhood is often linked to co-occurring conditions, why are we rushing to medicalise children instead of addressing their broader psychological needs?
The “Pause Button” Myth: Why Most Children Progress to Cross-Sex Hormones
One of the most misleading claims about puberty blockers is that they act as a “pause button” that simply gives children time to decide on their future. However, data from clinical settings contradicts this idea.
- Studies show that between 96-98% of children who start puberty blockers go on to cross-sex hormones, suggesting that blockers do not provide time for neutral exploration, but instead solidify a medical transition pathway.
- This phenomenon has been described as the “escalator effect”, where once a child is placed on puberty blockers, they are far more likely to continue towards irreversible medical changes.
- The idea that puberty blockers are fully reversible is also contested. Some researchers argue that the developmental changes missed during puberty may not be recoverable, even if treatment is stopped.
Given these findings, the NHS trial is not studying a neutral treatment—it is potentially leading children down a medicalised pathway with long-term consequences they cannot fully understand.
A Fundamental Safeguarding Failure
Medical ethics and child safeguarding principles dictate that we should not expose children to unnecessary risk, particularly when dealing with treatments that have unknown long-term effects.
Informed consent is a cornerstone of medical ethics, but how can a child truly consent to an intervention when even experts do not fully understand the consequences?
- Children and adolescents lack full neurological maturity to comprehend the lifelong consequences of medical transition.
- The idea that they can meaningfully consent to treatments that may cause infertility, sexual dysfunction, and cognitive impairment is ethically questionable at best, and medically reckless at worst.
- The role of social influence must also be considered. Research into social contagion and rapid-onset gender dysphoria (ROGD) suggests that some young people are influenced by peer groups, social media, and online communities, making it even more critical that clinicians exercise caution.
The NHS trial does not properly address any of these concerns. Instead, it assumes that the only ethical dilemma is whether puberty blockers work—not whether they should be used at all.
A More Responsible Approach to Gender Distress in Children
This is not about denying support to young people who are struggling with gender identity issues. It is about ensuring that medical interventions are based on rigorous scientific evidence and prioritise long-term well-being over ideological commitments.
A more responsible approach would include:
- Comprehensive psychological assessments before any medical intervention is considered.
- Addressing underlying mental health conditions that may be contributing to gender distress.
- Prioritising therapy and watchful waiting, allowing children to explore their identity without irreversible medical decisions.
- Long-term follow-up studies on individuals who took puberty blockers, particularly those who later regretted transitioning.
The first duty of medicine is to do no harm. If puberty blockers carry serious risks, cause irreversible changes, and lack strong evidence of benefit, then they should not be used on children—let alone tested on them in an experimental setting.
The NHS must put science, evidence, and safeguarding above ideology. Anything less is an unacceptable risk to the health and well-being of vulnerable children.