As of Sept. 8, 2014, there were 123,175 Americans waiting for transplants; 101,170 of these patients needed a kidney transplant [source: National Kidney Foundation]. But even if they receive a kidney tomorrow, it doesn't mean their worries are over. Seven percent of transplant recipients' kidneys fail within the first year, and 17 percent lose their new organ within three. The 10-year success rate is just 54 percent [source: Tushla]. The most common reason for a kidney transplant to fail -- or that of any transplanted organ -- is rejection, as the body's immune system fights what it perceives as a harmful, foreign body.
Scientists hope that in the future, custom transplantable organs will be available -- organs designed specifically for your body, probably using your own cells. These cells (suspended in gel) would either be used as the "ink" for a 3-D-type printer or they would be poured straight into an injection mold. Custom organs would alleviate long transplant waiting lists, plus combat the all-too-frequent organ rejection. Medical researchers are currently hard at work trying to grow everything from kidneys to ears to help people with failed organs or disfiguring injuries. Spinal discs have already been successfully replaced in rats; surely humans can't be far behind. As successes mount, the job of custom implant organ designers will be an important one [source: Sofge].