In many jurisdictions, adolescents acquire the right to consent to treatment; but in some cases their refusals – e.g. of life‐saving treatment – may not be respected. This asymmetry of adolescent consent and refusal seems puzzling, even incoherent. The aim here is to offer an original explanation, and a justification, of this asymmetry. Rather than trying to explain the asymmetry in terms of a variable standard of competence – where the adolescent is competent to consent to, but not refuse, certain interventions – the account offered here focuses more closely on the normative power to render actions permissible. Where normative powers are shared they can readily give rise to an asymmetry between consent and refusal. We then turn to why it is justifiable that normative powers be shared in adolescence. Transitional paternalism holds that the acquisition of normative powers by competent adolescents should not be an instant one, achieved in a single step, but that there should be a transitional period where paternalistic protection is rolled back, but not entirely withdrawn until a later date. Transitional paternalism could be implemented without generating the asymmetry between consent and refusal but, it is argued, the asymmetric version of transitional paternalism is to be preferred insofar as it offers a greater respect for the adolescent's decisions than the symmetrical alternative.