It's groundbreaking science. Two different laboratories have published techniques for producing embryonic stem cells without destroying embryos in Nature science journal (not available online without subscription). One technique doesn't destroy embryos, but the other method does in a way.
While there has been some commendable work done in researching the possible applications of human adult stem cells for therapeutic use, the reality is that embryonic stem cells have more utility. The reason is their totipotency - their ability to differentiate and develop into a huge variety of cell types. In contrast, adult stem cells are committed - they develop into the type of cell in the tissue they are part of. So adult muscle stem cells will rebuild muscle tissue, adult blood cells will replenish the blood and so on. Adult stem cells thus are more limited in their application than embryonic stem cells, and harder to harvest and grow in culture. But to date harvesting or producing embryonic stem cells has meant the destruction of embryos - an unethical technique.
Now two techniques have been presented which claim to avoid the unwanted destruction of embryos in the production of embryonic stem cells. You can read about those techniques in these articles from New Scientist and Nature News.
The first technique, reported by Rudolf Jaenisch and Alexander Meissner of the Massachusetts Institute of Technology, is called ANT (altered nuclear transfer).
