Opposition to `ownership' of cells and tissues often depends on arguments about the special or sacred nature of human bodies and other living things. Such arguments are not very helpful in dealing with the patenting of DNA fragments. Two arguments undergird support for patenting: the notion that an author has a `right' to an invention resulting from his/her labor, and the utilitarian argument that patents are needed to support medical inventiveness. The labor theory of ownership rights is subject to critique, (...) though it may still have enduring value. The more important argument is that deriving from the common good. If patents on DNA are supported on the basis of their contributions to the common good, then they can also be limited based on considerations of the common good. (shrink)