I just can't get my head around how that's ethical - it seems obvious to me [IANAME - I am not a medical ethicist] that the risks to participants outweigh the seriousness of the condition being studied - which most children just grow out of.
The Cass Review found that there was insufficient evidence that PBs were 'safe or effective'.
But hey, let's give them to a hundred or so kids anyway, what's the worst that can happen?
Well, if they turn out to be unsafe: Reduced bone density. Infertility. Mental health problems. A future enquiry into the ethics of how on earth this trial could have been allowed to go ahead. Litigation. Compensation...
But none of that seems to carry any weight.