In a new critically-acclaimed off-Broadway play, with a title too controversial for print, a gay man finds himself falling for a woman, which makes him - and his male partner - wonder whether he’s “really” gay after all.Can a gay man who is sexually attracted to women still be gay? And what about straight men who get turned on by other men? Are men “sexually fluid”?Female sexual fluidity - the capacity to move from romantic relationships with men to those with women, and vice versa - is well established, as I’ve previously discussed. Male sexual fluidity is less clear, yet it seems to be on the minds of many men and women. In fact, I’m often approached by women who are worried because they’ve caught their husbands or boyfriends looking at gay porn.According to psychotherapist Joe Kort there are plenty of reasons why a straight man might be interested in gay porn—and most of them aren’t signs that he’s questioning his sexuality. Likewise, a gay guy might get turned on by straight porn, but that doesn’t make him straight.“Many straight men are just curious about gay sex and how it works... or are turned on by gay male porn but have no desire to actually have sex with a man,” he explains.In other cases, straight men may be just looking for an anatomy lesson.“In our data, fewer than 2% of straight men searched for both gay porn and straight porn,” says neuroscientist Dr. Ogi Ogas, who, as coauthor of the book "A Billion Wicked Thoughts," analyzed a billion Internet searches and other sources of sexual data. “Yet straight men do search for images of penises - especially large penises - almost as often as they search for vaginas.”So it’s possible that these men aren’t necessarily interested in sex with other men, but are simply comparing their own anatomy to that of other guys.A man could also be looking for new fantasies: If he’s a heavy porn user, a straight man may peruse gay porn as his ability to become aroused by straight porn ebbs and his tolerance to sexual imagery increases. Some guys say they surf porn the way they surf TV channels, and what they stop on depends on their mood or the interest level of the content itself.It’s this tendency to focus on sex acts themselves, rather than gender, that partly helps explain male sexual fluidity, says Kort.“Straight men may go to Craigslist and get turned on by the descriptions of sexual acts with other men, but aren’t actually turned on by the men themselves,” he explains. “This is what separates ‘mostly’ straight men from gay men.”One thing is clear, though: Society is a lot less accepting of male sexual fluidity.Elisabeth Loyd, an affiliated faculty scholar at Indiana University’s Kinsey Institute for Research in Sex, Gender and Reproduction reports that many men themselves say they find their potential for sexual fluidity “very threatening.” And Kort tells me that he’s been criticized by some in the gay community for his view on male sexual fluidity because the concept of sexual fluidity implies that sexual orientation may be more a matter of choice than genetics.Sadly, it seems that women are freer to explore sexual fluidity - either in fantasy or reality.“Women have more permission to be sexually fluid, or even to just be physically loving and affectionate with female friends,” says Kort. “Men do not have these permissions without being labeled as forever ‘gay’.”Indeed, we seem to feel the need to force men to define their sexuality as “gay” or “straight”. The results of a recent study in the journal Biological Psychology may help change that. The study demonstrated that some men who say they’re “bisexual” actually do get aroused by both men and women - a big change from an earlier study found no proof that male bisexuality exists.And some research suggests that acceptance of both male and female sexual fluidity may increase with younger generations: According to Cornell University psychologist Ritch Savin-Williams more teenagers and young adults are avoiding such labels as “gay,” “lesbian” or “bisexual” altogether or are inventing new descriptions, such as “mostly straight.”And living life, rather than focusing on labels, is a large part of what sexual fluidity is all about.