There is much controversy in the news-both scientific and popular-about the use of embryonic stem cells for research. These cells are grown as cell lines in culture, created by taking the inner cell mass from 5-day-old embryos. What is the center of the controversy?
◦ the fact that the embryos are mostly those unused by in vitro clinics
◦ the knowledge that these cell lines have reverted spinal cord injuries in mice
◦ the unproven usefulness of stem cells to treat human disorders
◦ the realization that these cells are pluripotent rather than totipotent
◦ the difference of opinion about whether these embryos are persons