The president of Catholic University has decided to use a “slightly old-fashioned remedy” in an effort to curtail the binge drinking and casual hookups of students: getting rid of the coed dorms.

“We just thought it was a more wholesome environment,” said John H. Garvey, who became president of Catholic last year. “A little separation is a healthy thing.”

Eleven of the university’s 17 residence halls are coed, so a campuswide transition will take a few years. This fall, the university will place most freshmen in all-women or all-men halls. The next school year, sophomore halls will go single-sex. Then upperclassmen halls.

The decision to return to single-sex dorms, after more than two decades, stunned many students and alumni, who have built friendships and memories in coed environments, although some people outside the university may have been surprised that it had coed dorms in the first place.

“It’s easier to make more friends when its coed,” said Rachel L. Martin, 19, who will be a sophomore this fall. “It’s not just the same cliques of girls on the floors.”

Even in its coed dorms, the university still assigned women and men to their own floors or wings — and strictly enforced “visiting hours.” Some questioned just what sort of impact the new policy would have.

“College people are going to be drinking regardless of if there’s a girl living above them or below them,” said Bill Durdach, who graduated in May and once oversaw a floor of 52 male freshmen in a coed dorm. As for same-sex dorms: “Their behavior isn’t any different. And sometimes it’s worse,” Durdach said.

The coed vs. single-sex debate harkens back at least a generation, and today most colleges house female and male students under the same roof. Some schools even allow those students to be roommates. George Washington University is one of the latest campuses to offer “gender-neutral housing,” which allows students to live with anyone they choose.

But that's not an option all students want, said Erwin Villanueva, a rising junior at Catholic.

“It was a big relief to my Mom” that Catholic offered single-sex housing, Villanueva said. “I guess she’s just old-fashioned. She’s more comfortable with this.”

Many colleges started housing men and women under the same roof in the 1960s and ’70s, when women began to enroll more quickly than colleges could build housing, said Brian J. Willoughby, an assistant professor at Brigham Young University who studies university housing trends.

“The whole transition took place without a lot of outside evaluation,” Willoughby said. ”It was all driven by student demand.”

Today, he says that more than 90 percent of college students live in coed dorms and that many schools rarely receive requests for single-sex halls. Although some religious or socially conservative schools have never added a coed option, Willoughby said he doesn’t know of any schools that have taken that option away from students.

Willoughby’s research has also found that students in coed dorms are more than twice as likely to report weekly binge drinking or to have several sexual partners in the course of a year.

Garvey points to this research in explaining his decision, which he called “countercultural,” in an op-ed published in the Wall Street Journal on Monday. In that piece, Garvey wrote that virtue and intellect are connected, so helping students make ethical decisions enables them to learn better — and to stay safe, healthy and out of trouble.

Garvey said he first mentioned the idea to trustees and university leaders when he applied for the presidency and ran it by students during the school year. The idea was also vetted by Garvey’s wife, their five children and family friends.

“The girls said, ‘I don’t want to worry about going down the hall to take a shower and running into a guy,’ ” Garvey said. Although Catholic separated the sexes, “there’s a lot of circulation between the floors.”

He also said he had yet to hear about any genuine benefits of coed housing.

A group of students who graduated a few years ago are drafting a joint letter to Garvey to explain some of the benefits they found in coed housing.

“A lot of us met our spouses there,” said Ian Swank, 27, who graduated with a politics degree in 2006 and now lives in Silver Spring. “At Catholic, they basically promote ‘become a priest’ or ‘get married.’ . . . We’ve started families thanks to coed living.”