This paper focuses on a hypothetical case that represents an intervention request familiar to those who work with individuals with intellectual disability. Stacy has autism and moderate intellectual disability. Her parents have requested treatment for her hand flapping. Stacy is not competent to make her own treatment decisions; proxy consent is required. There are three primary justifications for proxy consent: the right to an open future, substituted judgment, and the best interest standard. The right to an open future justifies proxy (...) consent on the assumption of future autonomy whereas substituted judgment justifies proxy consent via reference to past autonomy. Neither applies. Stacy has not been, nor will she be, competent to make her own treatment decisions. The best interest standard justifies proxy consent on the grounds of beneficence. It is unlikely that hand flapping harms Stacy. None of the three primary means of justifying proxy consent apply to Stacy’s case. (shrink)