*Editor's note:** Soledad O'Brien investigates what it takes to succeed in science and technology fields in "Black in America: The New Promised Land – Silicon Valley" at 8 p.m. and 11 p.m. ET on December 18 on CNN.*

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**Stephanie Siek**, CNN**(CNN)**-- The idea that boys are innately better at math than girls does not add up, say researchers whose analysis of international math tests showed girls have the same ability as boys to succeed in math.

"If you take the averages worldwide, you do not see any gender gaps -- boys and girls perform about the same, on average," said Jonathan M. Kane, one of the study’s authors.

"Debunking Myths about Gender and Mathematics Performance," by University of Wisconsin researchers Kane and Janet E. Mertz, suggests that cultural and social factors predict whether someone is good at math -- not gender.

"We have to stop selling T-shirts to girls that say, 'I'm too pretty to do math,'" Kane said. "Our stereotypes are hurting our math education. If you take half the population and lecture to them about how girls aren't good in math and how no one will expect you to do well in math because you're a girl, you're building-in the cultural factor that makes girls not perform as well."

The study, published in the January 2012 issue of Notices of the American Mathematical Society, analyzed data from 86 countries through two international standardized tests: the Programme for International Student Assessment and Trends in International Mathematics and Science Study. It also looked at how girls and boys perform at the highest end of the math ability spectrum, in elite competitions like the International Mathematical Olympiad or in SAT math tests administered to students under age 13.

Kane and Mertz examined several theories about gaps in the math performance of girls and boys. One, the "greater male variability hypothesis," theorized that males have a naturally greater range of intellectual ability, with males forming a majority of those with extremely high ability and a majority of those with extremely low abilities, so males would tend to be the most high-achieving in math. If this were the case, the test results would show that boys tended to have the highest scores in every country, and that over time, they would continue to be overrepresented at the elite level.

But the researchers found that in many of the countries they compared, there was no gap between girls' and boys' average scores on the tests or between their performance at the elite level. In other countries, including the United States, such a gap existed in the past, but had narrowed with time. In the 1970s, there were 13 boys for every one girl who scored exceptionally high on the SAT math test as a child. By the 1990s, the ratio had decreased to three boys for every one girl.

The researchers also found that countries ranked higher on gender equity -- how women perform relative to men in education, health, political power and economic participation -- have higher math scores for both girls and boys. The United States ranked 31 out of 128 for gender equity, and on some tests, there was no gap between boys' and girls' test scores.

But even as the gap between boys' and girls' math scores has closed and the number of women pursuing math fields has increased, women remain underrepresented in elite university math departments, for example.

"What we really need to do is change our culture to tell people regardless of their gender, that they should try to be whatever they want to be," Mertz said. "For the U.S. specifically, we need more math certified teachers teaching math, especially in middle schools, and another thing we need is a more equitable society in which there are fewer kids growing up in poverty."