This scandal could derail the creation of the World Stem Cell Hub that was announced just last month. The goal of the Hub is to produce and distribute to researchers all over the world lines of stem cells derived from cloned human embryos. Many researchers believe that cloned stem cell lines derived from genetic material from patients with various diseases will shed light on how those diseases begin and will lead eventually to treatments.

This scandal provoked the old Watergate question: What did Hwang know and when did he know it? Regarding the purchased eggs, Sung Il Roh of the Mizmedi Hospital in Seoul, who collaborated with Hwang, admitted that he bought the eggs used in the cloning research from 20 women. Roh says that Hwang did not know that he had paid for the eggs. Roh paid each woman about $1,500 for their eggs.

What about the eggs "donated" by junior researchers in Hwang's lab? At a news conference yesterday, Hwang said that the young researchers volunteered to give him their eggs a couple of times and that he had turned them down. Hwang claims that it was only earlier this year that he found out that the women had gone ahead and donated their eggs using pseudonyms. Hwang says that he denied that they had donated eggs when asked about it by Nature because he wanted to protect the privacy of the women.

However, South Korea's Health Ministry issued a report yesterday that said an investigation of Dr Hwang had found that while the eggs had come from women scientists, there was "nothing legally or ethically wrong in the donation of ova by the researchers." In January 2005, South Korea outlawed commerce in human eggs, but all of the research under consideration here took place before that law was enacted.

For the moment let's set aside the issue of the eggs from the junior scientists. What's wrong with paying women for their eggs? The usual argument trotted out by bioethicists is that poor women will be "coerced" by the lure of filthy lucre to risk fertility treatments that boost their egg production.

To obtain eggs, women take hormones that cause their ovaries to superovulate, often producing more than dozen eggs at a time. The eggs are harvested by sucking them out of the ovaries with needles inserted through the women's vaginal walls. The hormone treatments produce some unpleasant side effects and perhaps 1 in 100 women experience ovarian hyperstimulation syndrome, a dangerous condition in which their ovaries swell up with fluid that must be drained at a clinic.

It is only right that women should be compensated for taking these risks. And in the United States it is perfectly legal to buy human eggs. The American Society for Reproductive Medicine (ASRM) guidelines suggest that payments for eggs be limited to $5,000. Meanwhile, the National Academies of Science issued its own set of guidelines for human embryonic stem cell research earlier this year. The NAS eschews any payments to women for their eggs above reimbursing them for their expenses, declaring that "no cash or in kind payments should be provided for donating oocytes for research purposes."

The ASRM guidelines set the $5,000 limit on the grounds that "the higher the payment, the greater the possibility that women will discount risks." A better way of thinking about paying more for eggs is that women will decide that the risks are worth the benefits that they get from higher payments. On the one hand, ASRM guidelines manage to condescend to women�the poor dears can't be trusted to make intelligent decisions about their own bodies�while on the other hand benefitting the bottom lines of reproductive clinics by trying to keep the price of eggs low. In any case, some clinics ignore the guidelines and pay $15,000 or more for a cycle of superovulation.

Paying for eggs is not illegal in the United States and the case that it is ethically wrong is far from clear. But what about the "donations" from Hwang's junior scientists? In this case, it appears now that the egg donations were sincerely voluntary�perhaps done out of an excess of research enthusiasm on the part of Hwang's young collaborators. Apparently, Hwang did not solicit nor knowingly accept egg donations from those researchers. Unfortunately, by breaking the rules, the young researchers have put in jeopardy the work they wanted to support.

Ultimately, Hwang's ethical offense is not using purchased eggs for his research. Hwang's real scientific crime is that he lied about it. Science depends absolutely on truth-telling by researchers. The real tragedy would be if Hwang's lies end up undermining the research he has worked so hard to advance.

 Ronald Bailey