Mao's colleague Tu Ching-fu has been studying cross-species organ transplants (xenotransplantation) for many years. He notes that the early organ transplant research program using non-human primates was quite successful. But because such primates are protected, they had to settle for the next best thing. Now, pigs, which are anatomically and physiologically similar to humans, are the focus of research.
養豬科學研究所應用生物系副研究員杜清富從事異種器官移植研究多年，他指出，早期器官移植多用與人類同屬靈長類的狒狒或黑猩猩作研究，但因牠們是保育類動物，只能退而求其次，改以解剖結構、生理功能和人接近的豬作研究對象。