This paper explores the notions of hope and how individual patient autonomy can trump carefully reasoned ethical concerns and policies intended to regulate stem cell transplants. We argue that the same limits of knowledge that inform arguments to restrain and regulate unproven treatments might also undermine our ability to comprehensively dismiss or condemn them. Incautiously or indiscriminately reasoned policies and attitudes may drive critical information and data underground, impel patients away from working with clinical researchers, and tread needlessly on hope, (...) the essential motivator of patients, advocates and researchers alike. We offer recommendations to clinicians and health care providers to help balance the discourse with individuals seeking treatment while guarding against fraud, misconception, and patient harm. (shrink)