Newly Discovered Source of Stem Cells Further Avoids "Ethical Problems"

Cells taken from men's testicles seem as versatile as the stem cells derived from embryos, researchers reported Wednesday in what may be yet another new approach in a burgeoning scientific field.

The new type of stem cells could be useful for growing personalized replacement tissues, according to a study in Thursday's issue of the journal Nature. But because of their source, their highest promise would apply to only half the world's population: men...