In light of the growing prominence of an age criterion in patient selection, it is essential to scrutinize the ethical legitimacy of arguments being offered both for and against using age as a criterion. Accordingly, the present study first explores the primary justifications for an age criterion, then examines the criterion's weaknesses. Weaknesses are grouped into two areas: deficiencies in the justifications of the criterion, and overarching critiques. Finally, a way forward in the midst of the present controversy is suggested. The study's conclusion is that an age criterion per se is unjustified, though age may play a carefully defined role in medical assessments relevant to patient selection.