As noted in a Betterhumans article on the topic, scientists are continuing to experience contradictory results with adult stem cells. The level of plasticity - the all-important ability to transform into other cell types - is under question. Without plasticity, adult stem cells are unlikely to be useful for regenerative work, such as growing replacement organs.
Adult stem cells from the brains of mice have proven to differentiate into blood vessel cells in an experiment that could help settle controversy over their potential.
However, it contradicts more recent findings that adult stem cells don't form new cells, but instead fuse with existing cells, forming a hybrid that takes on the pre-existing cell's function.
As is usual when research results appear to contradict one another, it seems that there are other mechanisms at work. Different populations of adult stem cells in the body may have different levels of plasticity. Furthermore, positive results seen to date in trials may or may not reflect on the utility of a given type of stem cell. In the long run, scientists will figure out how to make any cell perform any needed task as a part of future regenerative medicine - but the long run isn't good enough for people who are aging, suffering and dying now.
Sadly, political restrictions on stem cell research and therapeutic cloning in the US don't appear to be going away this year. An enormous amount of effort has been put into fighting or bypassing politicians on this issue, and justified effort it is too. However, elections will always be more important than lives to a certain set.
Still, as recent Senate hearings intended to hype adult stem cell research (as a way of building support for a ban on embryonic stem cell research) show, anti-research politicians and their proposed policies are now experiencing a lot more opposition. You can help!
In addition to writing to your elected representatives, you can further the cause of regenerative medicine by joining and supporting a number of active groups: