With a clutch of new university departments, a growing number of small biotechnology companies, a dedicated journal and regular outbursts of press hoopla, regenerative medicine is on a roll. From diabetes to Parkinson’s disease, from ailing hearts to failing knees, enthusiasts foresee new remedies for many of the common failures of flesh and bone.

The ambition of regenerative medicine—the reversal of age related, disease induced, and other bodily impairments—is hardly new. Varieties of “live cell therapy” dating back to the 1930s once lured the rich and famous to exclusive Swiss clinics to pay for expensive injections of heaven knows what. Such optimistic, if not foolhardy, leaps in the dark are a world away from current hopes and claims: the product of hard won insights into the biology of stem cells, and the genetic basis of their unique properties. And then there was the recent transplant of a bioengineered bronchus by a Spanish team of surgeons working with a European team of scientists (BMJ 2008;337:a2676, doi:10.1136/bmj.a2676).