In The Wall Street Journal, Mike Vilensky discusses the increasing number of gay fraternities and lesbian sororities in New York and New Jersey.

When Syracuse University junior Aaron Goldsmith couldn’t picture himself at any of his school’s fraternities, he decided to start one where gay men would be in the majority.

“This is for people who might not fit in at other houses,” said Mr. Goldsmith, who will launch a Delta Lambda Phi colony at Syracuse in the fall. “It’s bridging a gap between activism and social life.”

As people involved in Greek life on U.S. campuses seek to shed a reputation for raucous behavior and intolerant attitudes, fraternities and sororities founded by and geared toward gay people are gaining steam. Launched in 1986, Delta Lambda Phi has opened 14 of its 34 chapters or colonies since 2011 alone, according to a spokesman for the organization. (Colonies become chapters after three semesters.)

“It’s still in a growth pattern,” said Mr. Windmeyer, adding that the groups’ growth corresponds with an estimated rise in self-identifying gay people on campuses across the country. New York, in particular, offers myriad other social options for gay and lesbian students.

On a recent Sunday afternoon, members of NYU’s Delta Lambda Phi chapter were gathered in Central Park, practicing a dance routine for a coming intra-Greek variety show while enjoying coffee and doughnuts.

“I found out there was a gay frat, and I was like, ‘That’s fun. That’s what I’m looking for,’ ” said Mr. Limjoco, explaining why he joined.

Gamma Rho Lambda, a national sorority for lesbian women, has grown to 15 chapters or colonies since opening its first chapter in 2003, a spokeswoman for the group said.

“There have been gay people in fraternities and sororities for as long as they have existed, but these are for students who don’t want the traditional experience,” said Shane Windmeyer, director of Campus Pride, a group that works to make college campuses safer and more inclusive for all students. He said these groups guarantee social acceptance.

For some, it’s a shortcut to a social life. “It’s hard to meet people at NYU—let alone gay people—as a math major,” said Eric Limjoco, a member of New York University’s Delta Lambda Phi chapter.

In New York and New Jersey, the presence of such organizations is on the uptick, but still small, as individual colonies and chapters have struggled to attract large numbers. Delta Lambda Phi has a chapter of 25 members at New York University, which opened in 2008, and similarly sized chapters at Rutgers and the College of New Jersey. Gamma Rho Lambda has had a chapter at the State University of New York at Albany since 2011, which peaked at just over a dozen members.