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No, they’re good questions. Actually, the only technique that is commonly used today with adult stem cells is bone marrow transplants (but this can be used to treat a number of disorders, like leukemia, lymphoma, X-linked SCID, etc.). There have been some limited clinical trials for other adult stem cells; for example, trying to replace pancreatic islet cells as a treatment for diabetes. However, when you consider that the first bone marrow transplant was done in 1956, it seems as if these cell-based therapies move at glacially slow paces.

The reason ESCs haven’t been swapped out for adult stem cells is that the adult stem cells are very good at what they do - regrow the cells in the blood system. And there are potential problems with ESCs, such as cancers called teratomas, that using adult stem cells avoids. But by far the biggest reason that ESCs aren’t used today is that there are very few ESC lines. Thus, they’re almost certainly not going to be a genetic match to the recipient, and the recipient’s immune system will attack them. The adult stem cells, however, only regrow the blood system (and maybe heart tissue). They’ll never grow into a liver or a kidney, whereas ESCs potentially can.

Both sides of this stem cell debate tend to exaggerate enormously. However ESCs reach the clinic (and I’m praying that it’s the prolife iPCs that do so first - they hold more promise anyway), they’re not going to get there for another 20 years. The pro-stem cell people don’t acknowledge that fact readily.

However, ESCs do have a lot of therapeutic potential. And the reason that I think pro-life people should be honest about this is that people will feel like they can discount our opinion if we’re not honest up front. What it comes down to is that one innocent human life cannot be traded for another. And more power to the people that invent morally safe treatments such as iPCs.