Stem cell therapies show great medical promise, but few new products have made it into the marketplace. The translation of stem and other cell therapies faces not only challenges associated with research and development, but also the challenges of investment funding and regulatory approval. Regulators and investors alike appear to be voicing the same concerns: they see (1) insufficient high-quality data to provide confidence regarding the claims of medical benefit, (2) an insufficient understanding of the mechanism of action, and (3) a lack of identification of essential characteristics for product release criteria and for assuring reproducibility in manufacturing. The ensuing frustration on the part of researchers and developers may be the result of failure to fully comprehend what is required to assure that confidence.