extel, the basic idea is that everybody has stem cells.
you are born with them. they are in all your tissues. as you age, you use them up. then you cant repair yourself.
the only known source outside of body is cord blood, which is tissue matched to yourself, of course. and no body has definately used this source to produce many kinds of stem cells, other than blood, and the number of stem cells, and the plasticity of the what is in there, and even identifying potential stem cells is a problematic
celgen is working on it, as are other companies
it is thought that work on embryonic stem cells will enable study of early differentiation and identification of cellular markers on these early differentiating embryos / stem cells. you could then use this information to try to identify and manipulate stem cells in cord blood and adult tissues.
so there is a reason for scientific work on embryonic stem cells that is very much needed to further the work on your own stem cells. so like all campaign issues, it is truly muddy with the reality confused by the politics