Which gender is disadvantaged by the gap in math and science achievement largely depends on how academic achievement is being measured. Female students generally have better grades in their math classes, and this gap starts off very minimal but increases with age. However, males score higher on standardized math tests, and these score gaps also increase with age. Male students also score higher on measures of college readiness, such as the AP Calculus exams and the math section of the SAT.
The differences in National Assessment for Educational Progress (NAEP) math scores between boys and girls nearly double from the 9-year-olds to the 17-year-olds. This inconsistency in which gender shows more achievement could be due to the fact that class grades, especially in middle and high school, usually depend on a student's completion of homework assignments, and studies have shown that girls report spending more time on homework than boys. The gender gap in mathematics is particularly large among the highest-achieving students; for example, there is a 2.1 to 1 male-female ratio among students who score an 800 on the math portion of the SAT.
At least one study has challenged the existence of the gender gap in mathematics. In 2008 Janet Hyde and others published a study showing that male and female students did equally well on No Child Left Behind standardized tests that were administered in second through eleventh grades in ten states. However, Hyde and her team did find gaps that favored males at the upper end of the achievement distribution and tried to examine gaps on more difficult test questions (previous research has shown that males outperform females on more challenging items), but the tests they examined lacked adequately challenging items. This raised questions about whether there is still a gender gap in math achievement.
There is also a large discrepancy between the number of men and women working in STEM fields. Women have been, and continue to be, underrepresented in these fields. This underrepresentation is evident in the distribution of college majors among men and women; from 1997 to 2007, women earned only 18% of engineering bachelor's degrees.