For most surgical procedures and clinical interventions on children who lack the capacity to consent, a single consent from a person with parental responsibility for the child will suffice, provided it is given voluntarily and is informed by proper disclosure.

The great majority of such consensual interventions are lawful, legitimised by this single consent: “Consent is the legal flak jacket which protects the doctor from claims by the litigious…the doctor only needs one and as long as he continues to have one he has the legal right to proceed”.1

This simple formula is deceptive, because it is not always applicable. Requirements for consent differ. Female circumcision is proscribed by statute2 irrespective of the presence of consent, and there are other consensual activities that courts have refused to recognise as lawful. These include making ritualistic razor cuts on a child’s face in conformity with Yoruba customs;3 and impalement of the genitals with fishhooks and nails as part of sadomasochistic practices.4 Consensual decorative piercing of the genitals is lawful, although whether valid proxy consent could be provided on behalf of an incompetent child for such piercing has not yet been tested in court. Other interventions, such as the non-therapeutic sterilisation of a severely mentally handicapped child, cannot be made lawful simply by parental consent, and require the prior sanction of a court.5

What is rarely in doubt is whether more than one person needs to provide consent for the procedure. Children’s practice is made more interesting by the possibility of having both a competent child and two parents; any one of the three being able to provide valid consent. But only one is required.

This comfortable certainty is undermined by the discovery, within the common law, that judicial scrutiny has identified aspects of paediatric practice where both …