Word: embryos
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Arthur Caplan, director of the Center for Bioethics at the University of Minnesota, could conjure up several equally defensible ways in which cloning human embryos might be medically appropriate. Suppose, for example, a woman knew she was about to become sterile, either because of chemotherapy or through exposure to toxic substances. She might consider having an embryo cloned for future use. Or suppose a couple knew that their children had a chance of inheriting hemophilia or cystic fibrosis. Researchers have developed DNA-analysis techniques to screen embryos for such disorders, but the procedures require snipping cells off embryos, a process...
...corner, then just over the horizon. Ethicists called up nightmare visions of baby farming, of clones cannibalized for spare parts. Policymakers pointed to the vacuum in U.S. bioethical leadership. Critics decried the commercialization of fertility technology, and protesters took to the streets, calling for an immediate ban on human-embryo cloning. Scientists steeled themselves against a backlash they feared would obstruct a promising field of research -- and close off options to the infertile couples the original experiment had intended to serve...
...type cloning most people think of, in which genetic material from a mature individual -- or DNA from an extinct dinosaur -- is nurtured and grown into a living replica of the original. This is far beyond the reach of today's science. There is a vast difference between cloning an embryo that is made up of immature, undifferentiated cells and cloning adult cells that have already committed themselves to becoming skin or bone or blood. All cells contain within their DNA the information required to reproduce the entire organism, but in adult cells access to parts of that information has somehow...
...some couples cannot produce more than one embryo, perhaps because the man's semen is in short supply or the woman's ovaries are running out of eggs or do not respond well to hormone treatments designed to stimulate them into superovulating (producing large numbers of eggs on demand). A woman with only one embryo has about a 10% to 20% chance of getting pregnant through in-vitro fertilization. If that embryo could be cloned and turned into three or four, the chances of a successful pregnancy would increase significantly. This is the reason Hall and Stillman began experimenting with...
...scientists replicated their procedure many times, producing 48 clones in all. That was the entire experiment. None of the clones grew for more than six days. The scientists had no intention of starting an embryo factory, selling babies or doing anything else that ethicists worry about...