Female students nationwide have filed federal complaints that claim campus sexual-assault investigators lack training, fail to probe incidents adequately and treat attackers with too much leniency. Now, college men accused of sexual assault are protesting the same system.

Taking a page from the women’s complaints, men are citing violations under Title IX, the anti-gender discrimination law women have used to demand equality in sports programming and education for 40 years. Men are claiming that the investigations are biased in favor of their accusers, who are most often women.

Campus sexual-assault investigations represent a parallel criminal-justice system run by school officials without legal training in which evidence and the burden of proof are scant and punishments harsh, said Robert Shibley, senior vice president of the Foundation for Individual Rights in Education. The sanctions, which can include expulsion from college, are “massively life-changing,” he said. The process “makes someone guilty of what in most states is considered a felony.”

In the past two years, men disciplined or expelled have filed discrimination cases against Xavier University in Cincinnati; Vassar College in Poughkeepsie, N.Y.; Williams College in Williamstown, Mass.; Bucknell University in Lewisburg, Pa.; St. Joseph’s University in Philadelphia, and College of the Holy Cross in Worcester, Mass. The trend reflects a wider debate over how sexual assault is dealt with on campus and how that process differs from the broader criminal justice system. As a result, men and women are building cases under Title IX, interpreting the law to give themselves the best outcome.

Peter Yu, a Vassar student accused of sexually assaulting a female student last year, wasn’t allowed legal representation during the college’s investigation of his case, said his lawyer, Andrew Miltenberg. As a nonnative English speaker from China, Yu wasn’t able to tell his story, said a suit citing Title IX violations filed against the college.

“If you were a senior in college and had paid $200,000 for your education and were hoping to go to medical school, would you want to put all that on the line without a lawyer?” said Miltenberg.

Yu was expelled in March. Vassar officials declined to comment.

Title IX’s requirement that colleges provide equal opportunities in sports programming for men and women has been clear for decades, reshaping college athletics and women’s sports. The U.S. Education Department has been slower to define the law’s role in sexual assault, said Daniel Carter, director of the 32 National Campus Safety Initiative, an advocacy group in Centreville, Va.