In this paper I analyse who should be able to control the use of human embryonic stem cell lines. I distinguish between different kinds of control and analyse a set of arguments that purport to show that the donors of gametes and embryos should not be able to control the use of stem cell lines derived from their embryos. I show these arguments to be either deficient or of so general a scope that they apply not only to donors but also to those who derived the stem cell lines. Since we normally think that stem cell derivers have the right to control the use of the cell lines they derived, we have no justification for denying donors similar rights of control. In the final section I briefly discuss why informed consent is not an appropriate vehicle for transferring or alienating control rights.