The sterile conditions are not because of drug testing, but because these pigs organs are destined for transplantation into humans. The era of xenotransplantation has arrived. There is a 10-year waiting list in southern Italy for kidney transplants. It is estimated that 45,000 Americans could benefit from heart transplantation, yet only 2,000 human hearts are available annually. While it is true that pigs are less compatible with humans than are monkeys, they can be genetically manipulated to produce organs less likely to be rejected on transplantation.
Pigs quickly grow to full size, produce larger litters and can be reared in germ-free conditions.
There is a huge amount of hope and hype surrounding xenotransplantation. The process is not entirely novel, as pig heart valves have been used to replace damaged human ones without any ill effect. First there is the challenge of overcoming rejection. Rejection of transplanted organs can occur, even when genetic compatibility is maximised, as in the case of sibling donations. In kidney transplants, rejection is managed using powerful drugs, which suppress the recipients' immune system.