Science’s Jeffrey Mervis this week reports that the "time-honored practice of using introductory courses to weed out students seeking degrees in science and engineering hinders efforts to attract more women and minorities into those fields." Citing data from a survey conducted by the Bayer Foundation, in which "more than 400 chairs from the top-200 research universities and from minority-serving institutions responded to a series of questions on their attitudes toward underrepresented minorities," Mervis