Intrigued by the interviews with high school valedictorians that the Raleigh, N.C., News & Observer publishes this time each year, researcher E. Ann York decided to gather up three years' worth of its stories to look for any gender differences in the aspirations of these highest-achieving local students. Were boys more likely to strive for careers in engineering and math and to aim for more-selective colleges? Were girls opting for the humanities and the so-called "caring sciences," such as medicine? The answer was yes. While the sciences were a popular choice of college majors overall for this select sample of 150 valedictorians from seven counties, the boys were more likely than the girls to say they planned to study math, computer science, or engineering. The girls gravitated to the humanities and social sciences. And, even though the two groups had virtually identical GPAs, the boys were more likely to enroll in highly competitive colleges. Ms. York's study, it turns out, provides a pretty apt description of the national picture on gender representation in the STEM fields--science, technology, engineering, and mathematics. At a time when growing numbers of studies show that U.S. women have achieved parity, or are close to it, on science and math achievement tests, men still outnumber women at the top levels of many of those fields, particularly in quantitative sciences such as engineering and math. A handful of studies over the past few years are beginning to suggest that there may be a simple explanation for the persistent gender gaps in those fields. Women may just not want to pursue high-level careers in math and science, whether because they're not interested in those fields or because they perceive them to be less compatible with the family lives they hope to shape for themselves. Experts along the continuum of opinion agree that the issue is becoming increasingly important, given all the worry that the United States may be losing its competitive edge over the rest of the world in science and engineering fields. If more women were to enter the STEM fields and succeed in them at high levels, experts reason, the United States could expand its pipeline for math and science talent.