Women may be pleased to hear that reports from Maine claim to show what many say they have long known to be true — boys are not as smart as girls.

An article published in Maine’s Portland Press Herald last Sunday, which included comments from Yale Child Study Center researcher Walter Gilliam, cited figures to indicate that boys nationwide are lagging behind their female classmates when it comes to achievement in the classroom, from preschool to higher education. But some professors at Yale who have conducted research on the gender gap in education said this is far from the whole picture.

The original article, “The New Gender Gap,” said boys are scoring lower than girls on standardized tests in Maine. It also reported that twice as many boys as girls need special education services and that men earn fewer than 40 percent of the bachelor’s degrees awarded in Maine. And this general academic disparity can become noticeable before children have even reached kindergarten.

Gilliam recently conducted a study that has shown boys to be more than four times as likely as girls to be expelled from preschool. Gilliam also said that black preschoolers were more likely than their white or Hispanic counterparts to be expelled, and that black boys were at exceptionally high risk of being expelled. Explaining this phenomenon is more difficult, Gilliam said.

“There were those who wondered whether or not teachers or directors were more likely to pull the expulsion trigger if the child was male or African American,” he said. “Is it the child, their living environment, community and family that results in higher expulsion rates, or is it the teacher?”

Gilliam said his study looked at expulsion rates among male and female teachers of different ethnicities, hoping to evaluate the relationship between the higher expulsion rate among male preschoolers the prevalence of women — specifically, white women — in preschool teaching. Gilliam said more than 98 percent of preschool teachers in the country are women, most of them Caucasian. In Connecticut, almost 75 percent of all teachers, from kindergarten through high school, are women, according to the Connecticut Department of Education.

But Gilliam’s study concluded that boys are four and a half times more likely to be expelled than girls, regardless of the teacher’s ethnicity or gender.

And this trend seems to continue throughout children’s educational careers: Almost 75 percent of disciplinary offenses in Connecticut schools are committed by boys, the ConnDOE Web site said.

The Portland Press article posited several theories to explain these phenomena, including the possibility that current teaching techniques favor girls over boys. But Gilliam said looking at research on educational achievement will usually yield a more normal distribution for girls.

“For boys, the distribution tends to be a little flatter in the middle, with a lot of high-achieving boys and a lot of lower-achieving boys,” he said. “Boys will either succeed very well at doing very well, or succeed very well at doing very poorly. You get these bumps at both ends of the distribution that don’t make a lot of sense.”

But Paula Armbruster, director of the outpatient clinic at the Yale Child Study Center, said that all research findings differ, and warned against making such generalizations when there are so many variables that need to be taken into account.

Robert Schultz, a professor at the center, also said that the statistical trends cited by the Portland Press article could likely be caused by differences in statistical variance between boys and girls.

“The bell curve is wider for boys,” Schultz said. “Boys are more likely to fall at either extreme than girls are. I don’t think it’s as simple as boys are having problems with standardized test scores, since they are also scoring at the highest extremes more often than girls.”

Schultz said this trend holds true for medical issues too, citing his recent study of autism. He said boys are four times more likely than girls to be diagnosed autistic, but that in girls the cases are less likely to be severe.

“Boys are just more vulnerable, and the dominant theory right now is that girls’ makeup is more conserved,” Schultz said. “The only rationale I’ve heard is that nature is trying to preserve the female ability to reproduce.”

Schultz said he has seen resistance to studies that scientifically demonstrate educational differences between boys and girls.

“Any time you talk about gender differences, you always run the risk of upsetting people,” he said. “Often, people don’t want to think of these differences as real or as having a medical reason, and seek to explain such disparities in terms of cultural differences only.”

Armbruster declined to assess Schultz’s conclusions regarding biological differences between sexes, but she said an increasing number of boys have been referred to the Child Study Center’s outpatient clinic in recent decades. Currently, she said, boys account for roughly 60 percent of the clinic patients.