Adult islet cell transplants have already allowed hundreds of juvenile diabetes patients to throw away their insulin needles, and even newer approaches, which do NOT use embryonic stem cells may be in human trials soon. For an overview see: www.stemcellresearch.org/facts/factsheet-04-03-02.htm.
In one new approach pioneered by Harvard researchers, injections of certain cells from the spleen have “re-trained” diabetic animals’ immune systems to stop attacking their own pancreatic cells, after which new insulin-producing cells can regenerate spontaneously.2
Adult stem cells have shown repeated success at forming true insulin-producing islets, and have successfully reversed diabetes in animals. Embryonic stem cells have shown no success.
Footnotes: http://www.cbhd.org/resources/stemcells/mcconchie_2004-06-16.htm