Stem cells have applications in organ and tissue repair, gene therapy, drug discovery, and bioartificial organs. Companies are trying to find, grow, and control human embryonic stem cells—totipotent progenitor cells that can give rise to all the tissues in the human body. Investors are intrigued by the opportunity--after all, Sandoz bought 60% of SyStemix at a big premium--but are unnerved by the early-stage of stem cell science, and the all-or-nothing races for patents.