about stem cell research

Embryos have stem cells. Certain tissues in adults also contain stem cells, although the range of cells into which they can develop is limited.
In 1998, scientists at the University of Wisconsin–Madison figured out how to collect human embryonic stem cells and make them grow. Since then, researchers have learned to mix stem cells with combinations of proteins called growth factors to make the cells grow into different types of cells. Now, the search is on for ways to use stem cells to treat injuries and cure diseases.
For example, stem cells could be extracted, turned into new bone cells, and then injected into weak or broken bones. Or, they could become nerve cells that could heal spinal cord injuries, skin cells that could replace badly burnt skin, or brain cells that could help people who have suffered brain damage. To repair heart muscle in a mouse, researchers inject adult stem cells into the muscle of the damaged wall of a mouse heart.
The possibilities are endless.
So far, embryonic stem cells appear to be more useful than stem cells that come from adults. Because an embryo's cells are still dividing and specializing anyway, its stem cells can still become almost anything. By the time we grow up, however, our stem cells have a more limited ability to diversify.