It is remarkable how much robotics research is promoted by appealing to the idea that the only way to deal with a looming demographic crisis is to develop robots to look after older persons. This paper surveys and assesses the claims made on behalf of robots in relation to their capacity to meet the needs of older persons. We consider each of the roles that has been suggested for robots in aged care and attempt to evaluate how successful robots might be in these roles. We do so from the perspective of writers concerned primarily with the quality of aged care, paying particular attention to the social and ethical implications of the introduction of robots, rather than from the perspective of robotics, engineering, or computer science. We emphasis the importance of the social and emotional needs of older persons--which, we argue, robots are incapable of meeting--in almost any task involved in their care. Even if robots were to become capable of filling some service roles in the aged-care sector, economic pressures on the sector would most likely ensure that the result was a decrease in the amount of human contact experienced by older persons being cared for, which itself would be detrimental to their well-being. This means that the prospects for the ethical use of robots in the aged-care sector are far fewer than first appears. More controversially, we believe that it is not only misguided, but actually unethical, to attempt to substitute robot simulacra for genuine social interaction. A subsidiary goal of this paper is to draw attention to the discourse about aged care and robotics and locate it in the context of broader social attitudes towards older persons. We conclude by proposing a deliberative process involving older persons as a test for the ethics of the use of robots in aged care.