Xenotransplantation research, as a part of biomedical research, investigates the question of whether it is possible to take living organs, tissues, or cells from animals and transplant them into humans. It is hoped that the xenotransplantation of organs will close the widening gap between the growing demand for organs and the limited supply of donor organs; cellular xenotransplantation aims at providing first or improved therapies for a variety of diseases.