Two weeks ago, Science published a paper by Bert Vogelstein and Cristian Tomasetti of Johns Hopkins University, which put forth a mathematical analysis of the genesis of cancer and sought to explain variations in risk at different tissues. The paper, and especially the news coverage (including by Science) that followed, came under heavy criticism and generated hundreds of comments. Journalists were accused of misinterpreting the study's results. Although some praised the paper for elucidating the role that chance—the accumulation of random mutations in stem cells—plays in cancer, others argued that the authors' conclusions were flawed or oversimplified. Science examines how this story was communicated and the challenges inherent to streamlining complex biology and statistics for experts and nonexperts alike.