(From the Times Online). Our cells are just complex protein machinery, which means there is no obstacle to one day building all the cells we need for any given medical usage from scratch, to order. For the near term, however, researchers are focusing on manipulating cells into desired states through signaling and growth: "It is hard to predict how the science will develop, but I think we could produce a basic prototype-induced stem cell made from a human adult cell within six months to a year. Within two to three years we may be able to create a stem cell that is indistinguishable from one taken from an embryo. What we cannot do, though, is to let the optimism over my science hold us back from conducting research on embryonic stem cells while we are waiting for the alternative ... The concept of artificially inducing adult cells to return to a stem-cell state raises [attractive] possibilities for organ transplantation. If, for example, a patient's skin cell could be reverted to stem-cell form and thence converted back into any other form of tissue - such as nerve, heart or other organs - it could then be transplanted without risk of rejection by the patient." Any advance that lowers the cost of regenerative research, such as by lowering the cost of creating suitable totipotent stem cells, will speed progress.