Drawing on a social construction theory of ownership in biological material this paper discusses which differences in biological material might motivate differences in treatment and ownership rights. The analysis covers both the perspective of the person from whom the material originates and that of the potential recipient. Seven components of bundles of rights, drawing on the analytical tradition of Tony Honoré, and their relationship to various types of biological material are investigated. To exemplify these categories the cases of a heart, (...) a kidney, stem cells and hair are used. (shrink)