A prosthetic surgical heart valve for smaller patients, in particular pediatric patients. The heart valves are smaller and more flexible, and may be incrementally expandable to accommodate growth in the patient. The heart valves are especially useful at the pulmonary valve position, where the opening and closing pressures are much lower than at the other native valve locations. The heart valves are formed of thinner and more flexible materials than aortic or mitral valves which enable them to open and close more effectively when subjected to the lower pulmonary blood flow pressures. Incremental expansion of the heart valves is enabled by a plastically-expandable stiffening band coupled to a valve member.