Nearly two years after the cloning of Dolly had everyone asking if there would ever be another ewe, South Korean researchers are claiming that the answer is yes. Using a technique already performed in Hawaii on mice, two Korean scientists have conducted what may be the first cloning of a human embryo. They implanted genetic material from a 30-year-old woman into an egg cell, and then let that cell divide twice before stopping the experiment to steer clear of a Korean ban on experimentation with more fully developed embryos. "What this represents is a refinement of the Hawaii technique," says TIME science reporter Dick Thompson.
But it may not be enough to prove that an actual cloning has taken place. "One crucial moment is the 16-cell point. Cells divide automatically up to four cells, but it's only after they have divided to 16 that you have a pretty good chance that it's going to work," says Thompson. Because the Koreans stopped the experiment well before that point, it's not clear that the embryo would have grown into a full-fledged human. Still, like it or not, several genetically identical cats have just been let out of the bag.