This article examines arguments concerning enhancement of human persons recently presented by Michael Sandel (2004). In the first section, I briefly describe some of his arguments. In section two, I consider whether, as Sandel claims, the desire for mastery motivates enhancement and whether such a desire could be grounds for its impermissibility. Section three considers how Sandel draws the distinction between treatment and enhancement, and the relation to nature that he thinks each expresses. The fourth section examines Sandel’s views about parent/child relations and also how enhancement would affect distributive justice and the duty to aid. In conclusion, I briefly offer an alternative suggestion as to why enhancement may be troubling and consider what we could safely enhance.