Nature Biotechnology replies:

It is still not clear that biotechnology needs optimists. Biotechnology does need people with vision—as researchers, managers, and investors. But if they see only goals, then their vision amounts to nothing more than good intentions or wishful thinking. If they see only their immediate circumstances, then their vision contributes merely to problem solving. It is those who can anticipate a series of eventualities and prepare themselves for concomitant action that are more likely to succeed in the long run. The risks in biotechnology are undeniable, and they stem from the unknowable of science and commerce. It is prudent to recognize and address those risks, not compound them by overly optimistic or foolhardy behavior.