In this undated photo released by the Hospital Clinic of Barcelona on Tuesday, Nov. 18, 2008, Claudia Castillo, center, the recipient of a windpipe transplant which used tissue grown from her own stem cells, poses for a photograph with her children in Barcelona, Spain. European doctors have performed a windpipe transplant with tissue grown from the patient's own stem cells, eliminating the need for anti-rejection drugs. (AP Photo/Hospital Clinic of Barcelona, HO)