The cloning news from South Korea is a big story—this is an important breakthrough in developing techniques for therapeutic cloning. What Woo Suk Hwang and Shin Yong Moon were able to do is to remove a nucleus from an adult human cell, insert it into an enucleated ovum, and stimulate it to divide and produce an apparently normal early human embryo. This is an important step, because it means the nucleus was 'reprogrammed' to function properly as relatively undifferentiated tissue, and that it could then make appropriate developmental decisions; cells derived from it successfully made that first big decision about whether to form the Inner Cell Mass (ICM), which generates the embryo itself, or the trophoblast, which forms the placenta. Furthermore, while they didn't try to raise the cloned embryo to the fetal stage (and the investigators have plainly stated that they oppose that kind of reproductive cloning), they did isolate ICM cells, grow them up as a cultured stem cell line, and have found that they are pluripotent—that is, they have the potential to develop into many of the normal derivatives, such as bone, muscle, gut, and nerve.

How this can be important to you: imagine that someday you are diagnosed with Parkinson's disease, a degenerative neurological disorder caused by progressive depletion of a set of dopaminergic neurons deep in your brain. One treatment that has been successful is that new dopaminergic cells can be injected into the brain; the only problem is finding a good source of such cells. With this technique, doctors could take a few cells from you, reset them to an embryonic state, stimulate them to grow into a dish full of nothing but dopaminergic cells, and inject your own tissue into your brain to correct the problem.

Another disease that might someday be corrected by this procedure is juvenile onset diabetes. This form of diabetes is caused by the loss of specific pancreatic cells that secrete insulin; one future treatment might be to grow a new set of pancreatic cells from the patient's own stem cells, and restore full function to the organ.

Right now, there are serious limitations to the procedure. The only cells that the investigators could successfully clone were extracted from the ovaries of fertile females, which leaves us guys (and many women) out. On the other hand, the way the breakthrough was achieved was simple hard work and variations in the way the nuclei were extracted, and there's nothing to say that opportunities to carry out further unfettered tinkering might lead to methods that would work for even the fraction of the population that isn't equipped with operational ovaries.

Unfortunately, there is also a political aspect to this news. The technique was developed at Seoul National University in South Korea. The richest nation on the planet with the largest number of biomedical researchers was not and is not able to participate in this revolutionary work, because the United States does not offer the opportunity for unfettered research in this field. Early in his administration, our president, pandering to the ignorant, anti-science, anti-research, anti-knowledge wing of his fandamentalist religious base, imposed a number of restrictions on research in reproductive technologies, and specifically limited opportunities for embryonic stem cell research. It's yet another instance of this administration allowing the ideology of the most backwards-looking, uninformed special interest group dictate science policy, crippling one of the most advanced and productive research establishments on earth. Chalk up another boneheaded science policy decision to those morons in the Bush administration.

(Chris Mooney also has several good articles on this topic.)