In a recent press briefing, stem cell research pioneers James Thomson and John Gearhart announced that, despite political obstacles and limited funding, stem cell research is progressing and clinical trials on human beings should begin within the next five years. The Why Files chronicles the first five years of embryonic stem cell research, covering the science, the politics, and the ethical issues behind this contentious topic (and a closer look at the both the promise and doubt in adult stem cells). The second website -- from CBS News -- covers the press briefing held by Thomson and Gearhart, and offers two interactive features on stem cell research and human cloning, as well as links to related CBS News stories.