THURSDAY, May 1, 2014 (HealthDay News) -- Girls have earned better school grades than boys for nearly a century, according to a new study.
And that includes math and science, even though it's long been believed that boys do better in those subjects, said the researchers at the University of New Brunswick, in Canada.
They analyzed 308 studies that included data gathered between 1914 and 2011, representing more than 535,000 boys and nearly 600,000 girls in more than 30 countries. Seventy percent of the studies were conducted in the United States.
Girls' advantage in school grades was largest in language courses and smallest in math and science. Girls' lead over boys in math and science was not apparent until junior high or middle school.
Overall, the gender gap in grades increased from elementary to middle school, and decreased between high school and college, according to the study published online April 28 in the journal Psychological Bulletin.
The findings show that recent concerns about a "boy crisis," with boys lagging behind girls in school grades, are unfounded because girls have long done better in school than boys, said study author Daniel Voyer and colleagues.
"The fact that females generally perform better than their male counterparts throughout what is essentially mandatory schooling in most countries seems to be a well-kept secret, considering how little attention it has received as a global phenomenon," study co-author Susan Voyer said in a journal news release.
A number of factors could explain why girls get better grades than boys, the researchers said. Parents might assume that girls are worse in math and science so they might encourage them to put more effort into those subjects.
The study authors also noted that previous research has shown that girls tend to study to understand the topics, while boys tend to be more performance-driven and focus on final grades.
"Mastery of the subject matter generally produces better marks than performance emphasis, so this could account in part for males' lower marks than females," the study authors wrote.
The American Academy of Pediatrics has more about school.