Scientists at the University of Pennsylvania have taken stem cell research in a novel direction, showing how the cells can be converted in the laboratory into egg cells like those produced in the ovary. The work has some theologians reconsidering their ideas about the nature of life.

Use of such eggs might make therapeutic cloning - the idea of repairing patients' tissues by cloning their own body cells - ethically more acceptable to those who object to it. Further, the unfertilized eggs seem capable of developing parthenogenetically, or without the help of sperm, into embryos. ...[more]