This chapter examines how even Principlism, despite its status as the dominant practical framework in medical ethics, struggles to account coherently for the inherent value of infants and children. While its four principles—beneficence, non-maleficence, respect for autonomy and justice—are represented as age-neutral obligations, each is in fact shaped by adult-normative assumptions that risk obscuring the value of childness itself. Beneficence is defended largely through an argument from relationships: society agrees that parents owe special duties to their children. Yet this agreement functions as a circular assertion rather than an explanation, ultimately offering infants protection through social convention rather than providing any account of their intrinsic value. Autonomy, conceived as rational self-rule, excludes infants by definition and Principlism’s attempt to rescue them by appealing to the agent’s duties leaves unexplained why non-autonomous humans matter morally. Justice too struggles to accommodate childness: drawing on Rawls, Principlism places infants within the moral community only as beneficiaries of paternalistic exceptions, not as bearers of value grounded in their own mode of being. The chapter concludes that although Principlism offers important practical protections for paediatric patients, it ultimately relies on adultness as the measure of moral status. Without an anthropology of childness, Principlism cannot fully justify the value it ascribes to infants and children.