Accused rapists have begun using the same anti-discrimination law as alleged victims to challenge campus sexual assault investigations.

Men are claiming the investigations are biased in a favor of their accusers, who are usually women, in violation of Title IX, which prohibits gender-based discrimination and has been used since the 1970s to promote equality in university sports programs and education.

Most universities conduct investigations of sexual assault claims apart from the criminal justice system, and attorneys for both accused rapists and their alleged victims say these probes are often conducted by school officials who lack proper legal training.

Attorneys for some men accused of sexual assault complain that these investigations can use flimsy proof to impose harsh punishments, including expulsion, because college sexual assault investigations use the “preponderance of evidence” as the standard of proof, as civil cases do, instead of proof “beyond a reasonable doubt,” as criminal convictions require.

"Those accused of sexual violence seem to want campus investigations to be more like 'mini versions' of the mainstream criminal system," wrote Maya Dusenbury, executive director of Feministing. "Considering how often that system also fails rape victims, that’s probably not surprising."

Men have filed discrimination cases in the last two years against Xavier University, Vassar College, Williams College, Bucknell University, Saint Joseph’s University and College of the Holy Cross.

College students face a growing risk of standing accused of sexual assault, said the attorney who sued Holy Cross after her client was accused of raping another student.

“One sexual encounter that involves alcohol, and the next thing you know you’re accused and expelled and branded for life,” said attorney Nicole Colby Longton. “Schools are going to push kids to have signed waivers before they have intercourse.”

Another attorney, who represents a Vassar student accused of sexually assaulting a woman last year, said her client is a non-native English speaker from China who was unable to tell his side of the story because he wasn’t permitted legal representation while the college investigated the claim.

“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 attorney Andrew Miltenberg.

The Obama administration published a letter in April 2011 emphasizing that colleges and universities would be in violation of Title IX by failing to address sexual assaults because the law requires campuses to be safe places for men and women.

The Education Department established guidelines for the probes, which are typically conducted by a small panel of school officials and must take less than 60 days.

Penalties may be appealed by accusers or the accused, and colleges can be sued for imposing sanctions.

After the new guidelines were established two years ago, reports of campus sexual assault jumped 14 percent over the previous year, to 3,771, and 30 percent higher than 2009.

Assault victims are increasingly filing grievances against their universities under Title IX complaints, including 30 in the past year.

One woman who filed such a complaint said sexual assault victims need Title IX protection to continue their educations without continued harassment from their attackers.

College probes of sexual assault claims can help provide that protection, because police investigations and criminal prosecutions can take years and publicly expose victims in the courtroom.

But the use of Title IX to fight assault charges raises a new obstacle for rape victims, women’s rights advocates say.

“Defense attorneys are trying to get the playing field back to where it used to be, where sexual violence was ignored on campus for fear of lawsuits,” said said Laura Dunn, founder of SurvJustice.