The High Court has cleared the way for the PATHWAYS trial of puberty blockers to begin recruiting children. Mr Justice Chamberlain refused permission for a judicial review, concluding that the claimants’ arguments had no realistic prospect of success. Recruitment can now start.
That is the legal position. It is not a scientific or ethical vindication. Courts decide whether regulators have followed the proper processes; they do not improve a trial design that was already open to serious objection. The judgment is worrying because it treats regulatory approval as the end of the matter, when the deeper problems with PATHWAYS remain untouched.
I have written about this before. The trial still looks less like a rigorous attempt to settle an important clinical question and more like an expensive mechanism for keeping a contested intervention available under the protective cloak of “research.” Here are ten continuing difficulties.
1. Lack of clear clinical intent
Ethical trials begin with a coherent clinical question. PATHWAYS is framed around “gender incongruence.” That is not a tightly defined medical diagnosis with an established mechanism. It rests on subjective feelings and, ultimately, on the contested idea that a child can possess an innate gender identity at odds with their sexed body. Cass noted that the treatment aims themselves were unclear—reducing dysphoria, improving quality of life, buying time to think, supporting exploration, or helping the child “pass” later. Several of these aims are contradicted by existing evidence. Without a clear hypothesis about how pausing puberty is supposed to help a specific group of children, it is hard to see what definitive clinical decision the results could ever support.
2. The design cannot isolate the effect of the treatment
Every participant receives the new psychosocial package. The only difference between the arms is whether blockers start immediately or after a twelve-month delay. There is no pure control group receiving psychosocial support alone. Wait-list designs of this kind are known to suppress natural recovery and can exaggerate apparent treatment effects. Any improvement in quality-of-life or mental-health scores can be attributed, equally plausibly, to the counselling, to the placebo effect of being “affirmed,” to the passage of time, or to regression to the mean. The delayed-start comparison is too weak to disentangle these confounders.
3. Follow-up is too short for the questions that matter
Primary outcomes are measured at two years. Bone mass, fertility, sexual function and adult mental health unfold over decades. A two-year window is long enough to capture short-term mood changes and short enough to miss the more serious developmental consequences. Promises of later registry linkage are not a substitute for designing the study around the right timescale from the start.
4. Existing evidence is still being ignored
Thousands of children already passed through the old gender services and received these drugs. The data-linkage study that might tell us something useful about long-term outcomes has been repeatedly frustrated, and the LOGIC study already provides baseline measures on a substantial cohort. PATHWAYS spends more than ten million pounds and recruits another two hundred children rather than first examining the large body of evidence we already possess. Cass recommended this work; proceeding without it reverses the proper order of priorities.
5. The risk-benefit balance remains unfavourable
The known or strongly suspected risks of prolonged GnRHa in healthy adolescents include impaired bone development, possible effects on brain maturation, disruption of reproductive and sexual function, and a very high likelihood of progression to cross-sex hormones. Evidence repeatedly shows that almost all children who start blockers continue to hormones. Against this is set a primary endpoint based on a short quality-of-life questionnaire. It is difficult to see how even a substantial short-term subjective improvement could justify the developmental costs for a condition that historically often resolved with time and ordinary support.
6. Meaningful consent is impossible to obtain
The participants are children, many with autism, trauma or other mental-health difficulties. They are being asked to agree to an intervention that may permanently affect fertility and sexual function, and that almost always leads to further medicalisation. The paperwork may satisfy the regulators. Whether a twelve-year-old can genuinely understand what is being traded—especially when expectations about “living as the experienced gender” sit uneasily with the legal reality of sex—is another matter.
7. Different stages of puberty are treated as one intervention
Children from early to late puberty are eligible. Blocking puberty at Tanner stage 2 is physiologically and developmentally different from suppressing it at Tanner stage 5. Cass herself identified only a very narrow potential indication. Pooling widely different stages makes the results harder to interpret and reduces the chance of clear guidance for clinicians.
8. Multiple outcomes create a risk of selective interpretation
The trial collects a wide range of measures—quality of life, mental health, cognition, bone density, brain imaging and more—yet it is powered primarily for change on a single short questionnaire (KIDSCREEN-10). That instrument was not designed as a treatment outcome measure. With dozens of secondary endpoints and limited statistical power for most of them, there is a clear risk that whichever result looks most favourable will be emphasised, while less convenient findings receive less attention. This is a familiar problem in contested areas of medicine.
9. Expectancy effects and the absence of blinding
Everyone knows which arm they are in. The immediate group experiences the powerful signal of having their wishes granted; the delayed group may feel denied. Subjective outcomes are especially vulnerable to these effects. The design does little to mitigate the resulting bias.
10. A smoke screen for business as usual
This is the most troubling point. PATHWAYS allows the continued use of puberty blockers under the respectable banner of research. For those whose commitment is primarily ideological—who believe that affirmation is the only ethical response and that any questioning of medicalisation is hostility—the trial serves a useful purpose. It keeps the intervention available, generates numbers that can be interpreted in multiple ways, and postpones the moment when the NHS might have to conclude that the treatment never had a secure clinical foundation. The intent, in other words, looks more ideological than clinical. The trial becomes a mechanism for preserving an approach rather than testing it to destruction.
None of this is settled by a High Court ruling on the lawfulness of the regulatory approvals. The scientific and ethical questions remain. Two hundred childhoods and a large sum of public money are about to be committed to an experiment that, on present design, seems unlikely to answer them cleanly.
I remain, as ever, watching.
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