Continuity Argument
According to the continuity argument, the development of an embryo into a born human being progresses so continuously that it is impossible to distinguish clear-cut breaks that could then be used to justify a change in moral status. The dignity of a grown person therefore also goes back to the early embryo and, according to this argument, must be afforded to the early embryo.
Different Positions can be found in:
Holm, Søren (1996): The Moral Status of the Pre-Personal Human being. The Argument From Potential Reconsidered. In: D. Evans (ed.): Conceiving the Embryo. Ethics, Law and Practice in Human Embryology. The Hague/ London/ Boston.
Singer, Peter/ Dawson, Karen (1990): IVF Technology and the Argument from Potential. In: Peter Singer et al. (ed.): Embryo Experimentation. Ethical, Legal and Social Issues. Cambridge.
Ford, Norman M. (1988): When did I begin? Conception of the human individual in history, philosophy and science, Cambridge.
Brock, D. W. (2006): Is a consensus possible on stem cell research? Moral and political obstacles. In: Journal of Medical Ethics 32(1), 36-42. doi: 10.1136/jme.2005.013581 Online Version
Strong, Carson (2006): Preembryo Personhood: An Assessment of the President’s Council Arguments. In: Theoretical Medicine and Bioethics 27(5), 433-453. doi: 10.1007/s11017-006-9016-7 Online Version
Mauron, Alexandre / Baertschi, Bernard (2004): The European Embryonic Stem-Cell Debate and the Difficulties of Embryological Kantianism. In: Journal of Medicine and Philosophy: A Forum for Bioethics and Philosophy of Medicine 29(5), 563-581. doi: 10.1080/03605310490514234 Online Version