Peter Ostrander, the tireless coordinator and cheerleader for a renowned science and mathematics magnet program at Montgomery Blair High School in Silver Spring, Md., was not satisfied. Over the past few years, the pool of applicants had included nearly as many girls as boys, and the acceptance rate — based largely on test scores and grades--had followed suit. Yet when it came to which of the invitees ended up choosing Blair's magnet option over other offerings in the area, the scales tilted male. In 2012, for example, 80 percent of the eligible boys said yes, but only 70 percent of the girls. In 2010, the figures had been 93 percent and 56 percent. "The stereotype is out there that the magnet is filled with nerdy people," he said. "Whatever that means". The upper-class students took to the phone banks with verve. (Full disclosure: my daughter was one of them.) They talked of fun, extracurriculars and sisterhood. They secured many yes votes and earned pizza and sandwiches--but still, fewer qualified As a result, the demanding, gratifying, even thrilling four-year immersion in physics, chemistry, biology, calculus, computer science, astronomy, entomology, the proper use of power tools--and yes, the humanities and social sciences--remains almost two-thirds male. Montgomery Blair's experience is by no means unique. Even as girls prove their prowess in science and math, their ambivalence (矛盾心理) lingers when it comes to fields formerly painted boy blue. As researchers see it, that reluctance, that slight and possibly subliminal case of unfounded quantipathy (反数理学科情绪) , must be confronted and understood if the wider inequities in science are to be rooted out for good. Ample evidence refutes the notion that female brains just can't rotate the object, leap the quantum, do the math. Worldwide, girls' average math scores are on a par with those of boys. And even among math geniuses who score in the top ten thousandth of the population--the rarefied precinct notoriously deemed a boys' club by the former Harvard president Lawrence Summers--the male advantage has been shrinking steadily, to about 3 boys per girl today from 13 in the 1980s. Joseph Price of Brigham Young University and his colleagues reported this year that the gender gap in high-stakes math competitions disappeared simply by adding more rounds to a contest. Boys did better than girls in single-shot events, the researchers said, but when put through multiple rematches the boys fumbled, allowing the girls to catch up and often surpass them. Girls also excel in the classroom. Nationwide, their grade point average in high school math and science is 2.76 out of 4, compared with 2.56 for boys.