Debates about the legitimacy of embryonic stem-cell research have largely focused on the type of ethical value that should be accorded to the human embryo in␣vitro. In this paper, I try to show that, to broaden the scope of these debates, one needs to articulate an ontology that does not limit itself to biological accounts, but that instead focuses on the embryo’s place in a totality of relevance surrounding and guiding a human practice. Instead of attempting to substantiate the ethical (...) value of the embryo exclusively by pointing out that it has potentiality for personhood, one should examine the types of practices in which the embryo occurs and focus on the ends inherent to these practices. With this emphasis on context, it becomes apparent that the embryo’s ethical significance can only be understood by elucidating the attitudes that are established towards it in the course of specific activities. The distinction between fertilized embryos and cloned embryos proves to be important in this contextual analysis, since, from the point of view of practice, the two types of embryos appear to belong to different human practices: (assisted) procreation and medical research, respectively. In my arguments, I highlight the concepts of practice, technology, and nature, as they have been analyzed in the phenomenological tradition, particularly by Martin Heidegger. I come to the conclusion that therapeutic cloning should be allowed, provided that it turns out to be a project that benefits medical science in its aim to battle diseases. Important precautions have to be taken, however, in order to safeguard the practice of procreation from becoming perverted by the aims and attitudes of medical science when the two practices intersect. The threat in question needs to be taken seriously, since it concerns the structure and goal of practices which are central to our very self understanding as human beings. (shrink)