Last week, Woo Suk Hwang of Seoul National University finally admitted using eggs donated by graduate students and paid donors in his embryonic stem-cell research (see page 536). The admission raises pointed questions of the stem-cell research community worldwide and of the South Korean government and media. Each of these groups should be asking themselves why it has taken them so long to take this matter seriously

In the stem-cell research world beyond South Korea, the adverse publicity generated by Hwang's decision to resign as head of the World Stem Cell Hub should serve as a reminder — as if one was really needed — of the importance of transparent and stringent ethical behaviour by practitioners in this field.

Most of Hwang's international colleagues were slow to accept that anything was amiss in his laboratory. Even as the Korean authorities failed to properly investigate the allegations first made in this journal 18 months ago (Nature 429, 3; 2004), researchers seemed almost universally eager to establish fresh collaborations with the laboratory and to laud the quality and integrity of its work.

How can we know what ethical violations took place, given that there have been so many obstacles to finding the truth?

The withdrawal of collaboration by Gerald Schatten of the University of Pittsburgh on 12 November and Hwang's subsequent confession on 24 November are likely to quench some of that enthusiasm. These events have also opened the doors for South Korea's media to start looking more closely at the situation, something they were unwilling to do last year.

There are already signs, however, that some people in Korea are drawing the wrong conclusions from the episode. The government has promised to maintain financial support for Hwang, and the organizers of the stem-cell hub say they will refuse his resignation. The Munhwa Broadcasting Corporation, a Korean television network that broadcast a documentary critical of Hwang last week, has been hit by accusations that it is being unpatriotic, and several of the corporation's advertisers have dropped their accounts. On Internet chatboards, producers of the programme have been threatened with violence, and demonstrators have gathered outside the company's Seoul headquarters.

Roh Moo-hyun, the country's president, added his own thoughts to his presidential website on 27 November, calling for calm and branding the actions against the broadcasting corporation “absurd”.

Many in Korea still argue that Hwang's ethical lapse was not a serious violation, but merely reflects a difference in culture between Korea and the West. But how can we know what ethical violations —however they are defined — took place, given that there have been so many obstacles to finding the truth? The Korean national interest would best be served not by more flag-waving, but by the rigorous, official inquiry that has yet to be instigated into exactly what went on at Hwang's lab.