In 1972 Dr. Thomas Starzl, the renowned Pittsburgh surgeon who pioneered liver transplants, stopped performing live-donor transplants of any kind. He explained why in a speech in 1987: "The death of a single well-motivated and completely healthy living donor almost stops the clock worldwide. The most compelling argument against living donation is that it is not completely safe for the donor." Starzl said he knew of 20 donors who had died, though other doctors regard this number as miraculously low, since there have been more than 100,000 live-donor transplants.