The study, by cancer biochemist Janet Mertz of the University of Wisconsin-Madison and her collaborators, appears in the November Notices of the American Mathematical Society.

Mertz’s team tallied the participants in top international competitions for high school students, the William Lowell Putnam Mathematical Competition and the International Mathematical Olympiad, and other data. While girls were underrepresented on all countries’ teams, some countries, including the United States, often had no girls on a team.

The large discrepancies between teams point to cultural causes, Mertz says. “It’s not that girls don’t have the intrinsic attitude to excel at this level,” she says, “but that something’s happening in the U.S. to inhibit it.” In part, it may be the public’s attitude, she says. “They still believe this myth that girls can’t excel at math.”

Youth culture also may have an impact, branding students’ — not just girls’ — interest in math as “uncool,” the researchers write.

“It certainly resonates with my experience,” says Melanie Wood, who in 1998 became the first female member of the U.S. International Mathematical Olympiad team and is now a graduate student in mathematics at Princeton University. “There’s no question that doing math — and doing math for fun — was considered nerdy,” especially for a girl, Wood recalls of her grade-school years.

Other cultures may be less discouraging, judging from how many female students with exceptional skills emerge. The study found, for example, that in the history of the math olympiad, Bulgaria — a country with fewer than 8 million people — has sent a total of 21 girls. The United States has sent three.

From 1988 to 1997, the Soviet Union’s (and later Russia’s) teams were, on average, 20 percent girls. In the same period, the U.S. teams had none. Between 1984 and 1990, East Germany’s teams were 11 percent female, while West Germany’s were 100 percent male, Mertz points out, suggesting that genetic differences between countries, if they play a role, can’t be the whole story.

“It wasn’t really a surprise” to read the data, says Cathy Kessel, the Berkeley, Calif.-based president of the Association for Women in Mathematics. She says the results confirm anecdotal evidence about the differences across cultures, but also add to a number of studies demonstrating the role of culture in the gender gap. One such study, published in the May 30 Science, reported that gender differences in a standardized high-school-level math test varied greatly among 40 countries surveyed.

Mertz initiated the study in 2005, prompted by the controversy surrounding statements by former U.S. Secretary of the Treasury Lawrence Summers, who was then the president of Harvard University. Speaking at a conference on the gender gap in science and engineering, Summers alleged that the “different availability of aptitude at the high end” may play an important role.http://louis5j5sheehan.blogspot.com

In recent decades, Women have reduced, erased or inverted the gender gap in academic achievement. For example, slightly more women than men now graduate from U.S. colleges every year and women now earn one out of every four Ph.D.s in math.

But women are still underrepresented in most scientific professions, especially at the highest levels of achievement. According to the study, the nation’s top five mathematics departments (as ranked by U.S. News & World Report) employ 180 tenured professors; only eight are women.http://louis5j5sheehan.blogspot.com

To help understand that stubborn gap, Mertz says her team’s study focused on “the one-in-a-million student” — not just the kid who’ll be able to get a Ph.D. but the one who’ll be a Harvard professor. “It’s the first study I’ve seen that addresses the issue of mathematical talent at the very top of the spectrum,” says Wood.

Kessel says that in the United States the cultural reasons for the gap may go back a long way. “We have a long history of being focused on heredity,” Kessel says, and on the belief that intelligence is genetically determined, inborn and immutable, rather than something that can and needs to be nurtured. “The message I’d like people to carry away,” Kessel says, “is that cultural practices make a difference.” Louis J. Sheehan, Esquire