Animal eggs for stem cell research: a path not worth taking.

In January 2008, the Human Fertilisation and Embryology Authority (HFEA) (London, UK) issued two 1-year licenses for cytoplasmic hybrid embryo research. This article situates the HFEA's decision in its wider scientific and political context in which, until quite recently, the debate about human embryonic stem cell research has focused narrowly on the moral status of the developing human embryo. Next, ethical arguments against crossing species boundaries with humans are canvassed. Finally, a new argument about the risks of harm to women egg providers resulting from research involving the creation of humanesque cytoplasmic hybrid embryos is elaborated. Taken together these ethical concerns about the moral status of the human embryo, about the ethics of crossing species boundaries with humans, and about the potential harms to women (concerns that independently are more or less weighty for different constituencies), provide good reason to eschew humanesque cytoplasmic hybrid embryo research in favor of less ethically controversial means to the laudable end of successful regenerative medicine.