Will New Ways of Creating Stem Cells Dodge the Objections‪?‬

It's almost enough to make one yearn for the days when we knew little about human embryos. Now, thanks to the science of embryology, the possibilities for creating, slicing, and manipulating embryos are hard to keep track of. First there was in vitro fertilization. Soon it became possible to mix eggs and sperm to create embryos by the thousands. They could be sorted, graded, implanted, or frozen. If a man's sperm couldn't make it into an egg on its own, it could be sucked up into a needle and injected into the egg. After a few divisions but prior to implantation, a cell or two could be plucked from an embryo and analyzed for genetic defects--or to determine if it was compatible with an older sister or brother, so that if and when it became an infant the umbilical cord blood could be transplanted into that sibling to treat disease. Then we learned that scientists could take a five-day-old embryo--at that stage a hollow sphere with a collection of roughly a hundred cells stuck to an inside surface--break it open, spread out those hundred or so cells, and, with luck and skill on their side, create what are now called embryonic stem (ES) cell lines. Some embryos, it seems, are worth more busted up than whole.