#8. Stem Cell Breakthrough
In November, two groups of scientists in Japan and Wisconsin announced that they had found a way to reprogram human skin cells to behave like embryonic stem cells — without having to make or destroy any embryos. Embryonic stem cells are capable of turning into any of the 220 types of cell in the human body, so scientists have long touted them as a potential medicinal cure-all, from facilitating organ transplants to curing Alzheimer's. But detractors, including President Bush, who has banned federal funding of most embryonic stem cell research, say destroying embryos is immoral, no matter the health benefits. It's hoped that the new discovery could appease both sides of the stem cell war, paving the way for medical breakthroughs that do not require killing embryos.