Do boys perform better in math than girls? Do girls excel in reading?

The data vary.

Recent studies from Stanford University show that gender gaps in math proficiency still exist but are closing. And many factors besides gender influence how children learn, depending on their families' income and education.

Stanford looked at 260 million test scores in more than 10,000 school districts in the United States between 2008 and 2015. Researchers found:

— The math gap between genders has narrowed over the years.

— Boys outperform girls in math only slightly.

— Boys outperform girls in math in wealthy, suburban school districts.

— Girls outperform boys in math in low-income districts only slightly.

— Girls excel in English across all economic groups.

— Wealth likely plays a role in creating gender gaps.

"This study highlights that gender disparities still exist within the United States," said Erin Fahle, doctoral candidate in education policy at Stanford in northern California. "Our research is highlighting that both male and female students' educational opportunities are constrained by gender norms and stereotypes and our expectations for what they will do academically."

Overall, gaps among younger students in math and English performance are smaller than gaps among older students, Fahle told VOA. Her team looked at how parents invest resources in their children and how they speak with them.

Income factor

Family income can influence how children relate and interact with others, for example, by providing enrichment and educational activities. This can impact higher education, as well.

"Potentially, in the more affluent communities, parents are investing more in STEM [science, technology, engineering and math] opportunities in male children relative to female children," Fahle said.

Status also plays a role, according to researchers.

"The sons of 'high status' men get more years of education on average than the daughters, while the daughters of 'low status' men get more years of education on average than the sons," said Rosemary Hopcroft, a professor of sociology at the University of North Carolina at Charlotte.

This disparity between sons and daughters is not new. Two prior studies by Hopcroft, from 2005 and 2014 with colleague David O. Martin, have shown the same results.

Studies also were conducted by Boston College in 2003, the University of Pécs in Hungary and University of Liverpool in 1997 and the University of California-Davis in 1998.

Part of the reason studies differ is that conclusions about the gender gap in education are viewed differently, depending on a researcher's field of study.

"Generally, feminists usually are in favor of things that favor women. Well, this favors women, only women on one end of the socioeconomic scale, right, women from poor families," said Hopcroft. "And then it seems that boys at the top end of the scale are benefited."

"It's sort of very complicated, because it switches around, you see," she said.

Instructor bias

One study discovered "consistent evidence" that teachers give lower ratings to girls in math.

"Consistently, we see that teachers are rating girls as less capable than boys when the test is saying they are equally capable and the teacher thinks they are working equally as hard," said Joseph Cimpian, an associate professor of economics and education at New York University-Steinhardt, formerly known as the NYU School of Education.

"It's not clear why teachers hold beliefs that girls are less mathematically capable than similar boys," said Cimpian. "Teachers aren't necessarily aware of their own biases."

In addition, boys and girls have different approaches to problem-solving, and this is clear in their performances in mathematics, according to research from professors at the University of Illinois, New York University and West Chester University published in 2016.

"Boys are taught to be more of a risk-taker, and this may play out in the math classroom," said Sarah Lubienski, a mathematics education professor at Indiana University-Bloomington. Girls "dutifully follow the teacher's instructions and learn how to solve math problems by following rules, but they're less likely to score at the very top of the math achievement distribution, because of differences in problem-solving approaches."

The Stanford study may reveal a lot, but it also shows where more needs to be done, "to understand some of the phenomenons that we see," said Fahle.