Genetic engineering and the cloning of pigs have come together to encourage hope in the field of medical transplants. Some 60,000 people in the U.S. are on a waiting list to receive a new organ. Finding a donor is only the beginning, for every patient faces the real potential of having a new organ rejected immediately upon transplantation. Large quantities of powerful anti-rejection drugs are administered, but they weaken the person's entire system. Once the initial hurdle is passed, rejection is still possible and anti-rejection medication is necessary over the long term. Therefore, quality of life may be far from ideal. What can be done to improve the transplant patient's odds of finding a donor, surviving the surgery and not rejecting the new organ in the long term? Enter the common pig. Well, not so common, actually. Enter the genetically altered, cloned pig. Animal-to-human organ donation is known as "xenotransplantation." If the technology to grow acceptable animal organs can be mastered, an unlimited supply of organs will be available for transplantation into humans. The same technology that brought the world Dolly, the cloned sheep, has made it possible to clone pigs. That technology is nuclear transfer, removing the nucleus from an egg cell and replacing it with the nucleus of a cell that scientists wish to clone. Cloning pigs is more difficult that cloning sheep, cattle or mice-all of which have been done. Some new techniques were developed to make the cloning of pigs possible. Why work with pigs? The organs of a pig are closest in size to those of humans. Biogenetic engineering enables scientists to remove a gene that would cause the initial rejection of an organ, thus bypassing the first major hurdle to transplantation. They can also add genes that would slow the long-term rejection of the transplanted organ. The genetically altered pig could be cloned and reproduced as often as desired. Voilà-an "organ factory" is created. The first cloned piglets were born in March, announced the company that created Dolly, the cloned sheep. PPL Therapeutics Inc. has been working on the project for some time and sees the potential for medical use as "huge." Parallel research is ongoing in taking DNA from the patient who needs a new organ, and literally growing a new one. Nuclear transfer is also the basis for these experiments. Most likely the first application will be in creating insulin-producing cells to replace nonfunctioning ones in the pancreas of diabetics. This biotechnology, scientists project, will enable them to grow entire organs, including hearts, muscles, bones and skin. Advanced Cell Technology, a Massachusetts company, has been able to create embryos from cow eggs with the nuclei removed and replaced by human DNA. The cells grow into an embryonic life that produces human embryonic stem cells-the basic building block cells from which all cells grow. The biocommand that will "tell" the stem cells what kind of cell to grow into has not yet been discovered. The ethical questions are great. On the one side are those who see this as tampering with life and on the other side are those who see this as making life possible. Researcher Michael West, who works for Advanced Cell Technology, says that since they work with embryos that are less than 14 days old, "There is no human entity there." That's difficult to accept, when you believe as the UCGIA does, that life begins at conception. ("First Cloned Piglet Birth Near," UPI, Feb. 16, 2000; "Scientists Optimistic About Sheep Cloning Implications," UPI, Sept. 27, 1999.)