Hilary Cass and the Puberty Blockers Trial: Double Blind to Danger?
By Peter Jenkins
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Hilary Cass seems destined to be associated with controversy at every turn, following the publication of her groundbreaking review of gender identity services for children. After the UK publication of the Cass Review in April 2024, puberty blockers were banned on a temporary basis, with the ban being made permanent in December 2024 (DHSC, 2024). However, the use of puberty blockers for gender distress is now decisively back on the agenda again.
Pathways, a randomised controlled trial (RCT) into puberty blockers has been sanctioned and is due to begin this month. The trial is, however, decidedly not a classic ‘gold standard’ RCT. It is not ‘blinded’ and does not include a placebo i.e. ‘no treatment’ arm. The trial has already been heavily criticised on the grounds of its doubtful ethics, in exposing children to potentially harmful medicine. All in all, the stage is now set for what has been described as “one of the most controversial clinical trials in recent history” (Cohen, 2025: 1).
Perhaps surprisingly, relatively little has so far been said about the key legal concerns generated by the trial. The research Protocol seems to have carefully followed the guidelines for consent issued by the Medical Research Council, i.e. “Legally, consent is only required from one parent or person with parental responsibility”, as a child under 16 is not able to give consent in this situation (MRC, 2022: 7). However the NHS Health Research Authority guidelines further require that “Children and young people should be involved in the decision-making process whenever possible. You should ensure that they receive information about your trial, which is understandable to them” (HRA, 2024).
This places critical authority for consenting to the trial squarely on the parent or parents, or those with parental responsibility. This might seem to be simply just a legal technicality, a procedural glitch, but it actually trips something right at the heart of the controversy over children identifying as trans, namely the crucial role of parents. Children who have taken part in the trial’s comprehensive screening process in order to obtain puberty blockers are, it can almost be safely assumed, extremely likely to want to give their assent. In the somewhat understated wording of the trial’s Ethics Committee discussion, they clearly constitute “an engaged population” (LCE REC, 2025: 2).
But what of their parents? What are their views, their feelings, their own ‘lived experience’ of looking after a child who decides to identify as trans? Not much is known of these aspects, since this is apparently not a major research priority. What is often claimed is that parental affirmation of their child’s assumed trans identity is critical to protecting their child’s mental health (Travers, 2012).
The trial Protocol does accept that the use of puberty blockers “has elicited differing and often strongly held- and polarised views” (KCL, 2025: 21). However, it does not relate this clash closely enough to the complex process of obtaining parental consent, particularly where there is child-parent conflict over medical transition. The trial Protocol uses the term ‘gender incongruence’ as a diagnostic reference point, derived from ICD-11 (WHO, 2025). Yet gender incongruence can also be characterised as part of an all-encompassing belief system about gender identity. In effect, this latter belief represents part of a powerful political ideology, rather than describing simply a sexual health condition (Jenkins, 2024).
Some of the real depth and intensity of child-parent conflict over medical transition can be seen in the recent savage trans activist criticism of parents who are members of the Bayswater Group, a support group for parents of trans-identified offspring. “When Charlotte, then 22, came out as nonbinary, their parents reacted poorly. “My mum started crying,” they recalled. “They begged me not to take medication for a while, because they believed I should have consulted with them.” According to Charlotte, “My parents very clearly do not love me, they say”. “Liam, now a sixth-form student, experienced immediate rejection when he first came out in his early teens. His parents accused him of having been brainwashed, and took away his phone…” (Baker & Rocca, 2025).
The ideological pressure on parents to agree with their child’s assumed gender identity can be almost overpowering. This can produce a notional ‘double blind’ situation where both assenting child and consenting parent are blinded to the very real risks of taking puberty blockers, whatever the process for obtaining informed parental consent. In addition, conflict issues can be further amplified if one parent supports the child’s transition, and the other parent opposes it, for whatever reason. These crucial points seem to receive little detailed attention from the designers of the trial Protocol. In addition, the survey instruments for assessing perceived parental support for gender identity transition appear to endorse gender identity ideology. For instance, the questionnaire documentation claims that “… rejection may also be informed by parents’ faith-based beliefs, negative views of diversity in sexual and gender identity, or a lack of information on gender-affirming medical interventions” (Hidalgo et al, 2017: 181).
There is no acknowledgement here that parental ‘rejection’ might be due to their legitimately held beliefs about sex as a binary biological reality, or a wish to protect their child from the documented harms of unnecessary medical transition. The research instrument for parents explains that one purpose of the instrument is “to identify parents who may benefit from intervention to better support their transgender and gender expansive children” (Reguitti et al, 2022: 10: PJ: emphasis added). Both of the research questionnaires for parental involvement therefore appear to be strongly partisan and ideological in their nature, and are far from being simply neutral instruments for scientific study.
Fortunately, the courts have already identified that parental conflict over treatment for children with gender distress can be a serious consideration:
“My second particular concern is that of the pressure that may be placed by the children in issue upon their parents. Where a child has Gender Dysphoria and is convinced that s/he should be prescribed PBs, it is likely to be very hard for parents to refuse to consent. One does not have to be a child psychologist to appreciate the tensions that may arise within a family in this situation. I would describe this as “reverse pressure…”. The judge went on to state: “If the clinicians, or indeed any one of them, is concerned that the parents are being pressured to give consent, then I have no doubt such a case should be brought to Court” [AB v CD 2021 at 125].
Given this, the trial Protocol does not appear to fully recognise the gravity of the issue of potential parental conflict. The MRC guidance states that “…it is good practice to involve both parents and, if there is disagreement, then it is advisable to exclude the child from the research (unless it provides access to treatment that is otherwise unavailable)” (MRC, 2022: 7). At the relevant Ethics Committee, the research team stated that in the event of disagreement between parents over consent, “it was for the national MDT [PJ: Multi Disciplinary Review Team] to make the decision rather than the research team” (LCE REC, 2025: 5).
This approach is in sharp contrast with best practice as set out in the current Code of Practice for the Mental Health Act (MHA) 1983, which provides a useful point of comparison (DoH, 2015). This is a code with statutory authority, applying to professionals working within the remit of the MHA 1983 (now replaced by the MHA 2025). While the Code does not apply to children taking part in the puberty blocker trial, it does recognise some of the complexity involved in achieving valid consent from parents and in resolving inter-parental disputes over treatment decisions.
The Code identifies some of the situations where the validity of parental consent may be questioned, such as where “the specific form of treatment is particularly invasive and/or controversial”, such as electroconvulsive therapy, (DoH, 2015: 178); or where a parent is unable to focus on the child’s best interests, as in the case of an acrimonious divorce; or where one parent strongly opposes the treatment decision. “If there is doubt as to whether or not parental consent can be relied upon to authorise the particular intervention, professionals should take legal advice so that account may be taken of the most recent case law” (DoH, 2015: 179).
The current RCT into puberty blockers is therefore at substantial risk of taking a simplistic and unhelpful view of non-affirming parents. It also appears to side-step the very complex issues about resolving conflicts over parental consent, despite these conflicts clearly being recognised in recent case law. The trial’s reliance on one parent’s consent for this ‘invasive and controversial’ medical treatment may also provide a lower level of protection for the child’s interests than is currently mandatory for children in mental health services.
By Peter Jenkins, counsellor, supervisor, trainer and researcher in the UK. He has been a member of both the BACP Professional Conduct Committee and the UKCP Ethics Committee. He has published a number of books on legal aspects of therapy, including Professional Practice in Counselling and Psychotherapy: Ethics and the Law (Sage, 2017). https://uk.sagepub.com/en-gb/eur/counselling-and-psychotherapy-professional-practice/book243292
Peter is also a member of Thoughtful Therapists. His critique of the Memorandum of Understanding on Conversion Therapy was described as ‘instrumental’ in persuading the UKCP Board of the case for leaving the MOU in 2024.