What are some of the limitations of stem cells in terms of medical treatment?

New field: Embryonic stem cells have been spectacularly effective in treating wet macular degeneration in new studies and even most social conservative have stopped opposing them. Other stem cells can repopulate marrow after curative cancer therapy, repopulate a heart attack to improve survival, and much else. This is no longer "controversial" and much more will probably emerge soon.

LIMITS ON STEM CELL : Stem cell use is considered experimental and is not fda-approved for the treatment of any disease. Only adult stem cells can be used must be autologous - that is, your own cells minimal manipulation allowed - no culture to expand cell numbers and no additional treatments prior to use must be used for homologous purpose - per fda, must "perform the same basic function or functions.