In the most recent of his series of stunning articles on induced pluripotent stem (iPS) cells (T. Aoi et al. Science doi:10.1126/science.1154884; 2008), Shinya Yamanaka made a couple of small mistakes. Happily, he has since given plausible explanations for the mistakes, and has effectively argued that they do not affect the article's central conclusions — thus heading off worries (and one unsubstantiated accusation) that the errors signalled deeper problems with the article.

Still, the incident illustrates why there is cause for concern as scientists hop on the iPS bandwagon (see page 406). The very existence of such carelessness by the leading light of iPS cell research, a scientist known for his thorough, careful work, shows how much the race mentality has taken over the field. The paper was published online a mere five and a half weeks after it was submitted. Other key articles in the field show similar signs of being rushed for publication. One biotech company recently announced its iPS cell results without even bothering to publish (see Nature 452, 132; 2008). And authors have been pushing journal editors to speed up peer review — under the threat of taking the paper elsewhere — which puts even more pressure on the small circle of reviewers sufficiently versed in iPS cell science.

Competition is good. Indeed, it is a major reason why iPS cell research has flourished since 2006, when Yamanaka first showed that a handful of genes can reprogram a cell to a pluripotent state. Nonetheless, the fast-moving fields of science are showing some unpleasant tendencies. Researchers are cutting corners and making mistakes. They are making over-hyped promises that will probably be broken. And they are neglecting other valuable fields of research. All this has already been seen in iPS cell research.

Hype may also carry researchers away from their mission and raise the spectre of fraud. Indeed, as Alan Trounson, head of the California Institute of Regenerative Medicine in San Francisco recently told Nature Reports Stem Cells, “excessive” media attention on iPS cell research could “separate science from reality” in the same way it did during the therapeutic-cloning scandal surrounding South Korea's Woo Suk Hwang. “Cool heads and a close connection with the lab should prevail in order to ensure science progresses truly by reliable evidence,” he says.

The errors in Yamanaka's article are unfortunate — not least because they play into the hands of those who want to tarnish the science or the scientists. The criticism of Yamanaka's article came from an anonymous source who seemed bent on a personal attack. From the address “Reprogrammer Yamanaka” on 29 February, the e-mailer sent an account of Yamanaka's mistakes to journal editors, science journalists and scientists, scolding Yamanaka for his “embarrassing inconsistencies” and calling on him “to either retract their paper or provide meticulous and thorough new analysis”.

Yes, this attack was overly dramatic. And yes, Yamanaka owned up to his mistakes with commendable speed and honesty. But even so, this incident should be a wake-up call.

Post-Hwang, scientists and journals undertook much soul-searching about what went wrong. Some came to the bad-apple theory — that Hwang was just an anomaly. Most, rightly, saw it as a deeper problem that could affect any field of science. In the aftermath, many researchers vowed to redouble their efforts to guard against honest mistakes (usually attributed, as Hwang did at first, to the rush to submit articles), as well as against the whole spectrum of selective presentation of data, manipulation of images and outright fraud. iPS cell research may be the first substantial test of these efforts.