The EEOC released job discrimination statistics revealing that total complaints are on the rise for the first time in 4 years. See www.eeoc.gov. About one third of those total complaints are gender-based harassment complaints, that is Title VII related, and of those 15.4 percent were filed by men. Many of which allege they were harassed by other men.
It is my opinion that the instances of harassment have not increased but the tolerance level for harassing behavior has decreased. With the increasing sexual harassment training requirements and the overall awarness of the issue by the public, a new norm has been created in the workplace. A norm in which men are less willing to tolerate being told to act "like one of the guys", and more willing to state they are offended by off-color jokes, sexual comments or gender stereotyping. I think what this means for employers is that they have to be even more aware of the behavior going on in the workplace, even "between the guys". I often hear of jokes and comments being made that are inappropriate for the workplace but the defense is it was between friends and it was just a bunch of guys in the conversation, so how could anyone have been offended. I think some of those men are offended and they are now speaking out about it.
Update – There is a good article on the same subject at http://hotjobs.yahoo.com/jobseeker/tools/ept/careerArticlesPost.html?post=64 the atuthors have the same opinion of why male complaints of sexual harassment are up. This is definatley something employers should be aware of.