Proponents of embryonic stem cell research proclaim the potential of the research to find cures or treatments for many diseases such as Parkinson's and Alzheimer's. Opponents say the use and destruction of human embryos in the conduct of this research are immoral. In 2001, President Bush announced a ban on federal funding involving any new lines of embryonic stem cells. But calls to lift the ban continue, as do movements to increase funding at the state level. Which side of the debate is right? Is embryonic stem cell research ethical or not? Peter Robinson speaks with Ramesh Ponnuru and Irving Weissman.