"Despite the long history of using fetal tissue in medicine and research, the practice could be on the way out. Even though it has led to important medical advances in the last several decades, “in the future, the need for fetal tissue will go down because of advances in stem cell [technology] that will take over,” Hyun said. One of the earliest advances with fetal tissue was to use fetal kidney cells to create the first poliovirus vaccines, which are now estimated to save 550,000 lives worldwide every year."