We believe that these types of cells are actually more primitive and more flexible than the adult stem cells that would be found in bone marrow, ... They're much younger. They're more robust.

Adult stem cells tend not to form tumors.

Stem cells are probably going to be extremely useful.

There are currently 58 diseases that are being treated using adult stem cells so the issue of stems cells has a positive side, providing the cells are obtained ethically,

Adult stem cells are also problematic, as they are difficult to identify, purify and grow, and simply may not exist for certain diseased tissues that need to be replaced.

When we talk about stem cells, we are actually talking about a complicated series of things, including adult stem cells which are largely cells devoted to replacing individual tissues like blood elements or liver or even the brain.