CLONING GETS CLOSER

摘要

Back when it was no more than a cheesy science-fiction plot device, human cloning seemed like something that would eventually be revealed to a horrified world full-blown and fully grown- a monstrous carnival apparition ("The Amazing Cloned Boy!") out of a medical freak show. It hasn't quite turned out that way. Cloning has been emerging gradually, over the past decade, in small increments. Each advance has been startling enough, prompting ethical debates, cautionary references to Aldous Huxley's brave new world and calls for restrictive legislation. But there have been so many milestones, starting even before the birth of Dolly the sheep in 1996, that each one seems a little less startling than the one before. Sometimes an advance is so subtle that it sounds just like the breakthrough that made headlines the year before. That's how a report in the journal Science sounded last week- at least at first blush. Woo Suk Hwang and Dr. Shin Yong Moon, from Korea's Seoul National University, announced that they had created more than 200 embryos by cloning mature human cells and had grown 30 of them to the blastocyst stage of development, each more than 100 cells strong. This isn't the first time cloned human embryos have been produced: in 2001 the Massachusetts bio-tech firm Advanced Cell Technology made several. They all died quickly, but in a sense the first cloned human cells are actually old news.