Overall, 65 percent of the fraud cases were committed by males, but the percentage varied among the academic ranks: 88 percent of faculty members who committed misconduct were male, compared with 69 percent of postdoctoral fellows, 58 percent of students, and 43 percent of other research personnel. In each career category, the proportion of males committing misconduct was greater than would have been predicted from the gender distribution of scientists. The gender difference was surprisingly large among faculty, said Dr. Casadevall, who also holds the Leo and Julia Forchheimer Chair in/of Microbiology & Immunology. Of the 72 faculty who committed fraud, just 9 were female – one-third of the expected 27 if females had committed fraud at the same rate as males.The study did not examine why men are more likely to commit fraud. One possibility is that misconduct is biologically driven. "As research has shown, males tend to be risk takers, more so than females, and to commit fraud entails taking a risk," said Dr. Casadevall. "It may also be that males are more competitive, or that women are more sensitive to the threat of sanctions. I think the best answer is that we don't know. Now that we have documented the problem, we can begin a serious discussion about what is going on and what can be done about it." The researchers had hypothesized that the majority of cases of misconduct would involve trainees, who face intense pressure to publish – a critical step toward obtaining research funds. But they found that misconduct was spread rather evenly across the career spectrum. "You might think that as scientists go up the career ladder, they would feel more secure. But the bigger the lab you run, the more grants you need, which increases the pressures to publish and the temptation to cheat," said Dr. Casadevall.