In the first part of this article, I argue that even those entities that in their own right and for their own sake give us reason not to destroy them and to help them are sometimes substitutable for the good of other entities. In so arguing, I consider the idea of being valuable as an end in virtue of intrinsic and extrinsic properties. I also conclude that entities that have claims to things and against others are especially nonsubstitutable. In the second part, I argue that cloning poses no threat to the nonsubstitutability of these entities (and in this sense, to the dignity of persons). I also consider the relation between cloning and (what I called) holistic identity, and between the latter and genetic identity. In the concluding part of the article, I try to distinguish cases where identity over time and so-called person-affecting acts have and do not have greater moral significance than nonidentity over time and nonperson-affecting acts. I try to apply my results to cases involving embryos, future generations, and to the so-called Non-Identity Problem.