Colleges and universities these days are seeing a surge in enrollment — and it's increasingly driven by young women, according to U.S. Census data released yesterday.

The numbers confirm years of enrollment data showing that women have not only closed the college enrollment gap — they have far surpassed men on campuses. For every four men enrolled in graduate schools in 2006, there were nearly six women.

The numbers are disturbing to Leonard Sax, a Maryland psychologist, family physician and author of "Boys Adrift: The Five Factors Driving the Growing Epidemic of Unmotivated Boys and Underachieving Young Men." He says the data present a picture of "more and more young men who don't seem to have the drive that their sisters have."

Part of the Census Bureau's American Community Survey of 3 million households, the 2006 data are significant because they're the first since 2000 to survey Americans living in "group quarters" such as college dormitories, military barracks, nursing homes and prisons.

While the number of both male and female students rose between 2000 and 2006, the survey found, women outpaced men in both undergraduate and graduate programs. In that period, the nation's undergraduate enrollment swelled by nearly 2.7 million students, 18.7 percent, but the percentage who were male fell 1.2 points, to 44 percent.

Women in 2006 made up 56 percent of undergrads, up from 54.8 percent in 2000.

Sax says the enrollment numbers actually underplay the extent of the problem — and recent U.S. Education Department diploma data agree: Women last spring earned an estimated 58.5 percent of bachelor's degrees, up from 57.2 percent in 2000. They're expected to earn 60 percent of bachelor's degrees by 2012.

The problem these days begins when boys are barely enrolled in school, Sax says. Since the 1983 publication of "A Nation at Risk," which challenged schools to improve basic education, a widespread push to teach children to read in kindergarten has turned many boys off to books and learning because, for many of them, reading is developmentally inappropriate at such a young age.

And for many boys, their poor attitude about learning never improves.

"We now have second-grade boys who will tell you they hate school," he says.

After that, he says, they hit barriers that block the path to college: higher rates of doctor-prescribed attention-deficit hyperactivity disorder drugs, the lure of shoot-'em-up video games and a culture that, for many urban and minority boys, doesn't value education.

"Doing well in school and caring about your grades has come to be seen as unmasculine," Sax says.