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Over the past two decades, women’s has increasingly been seen as more fluid than men’s. Many studies have offered evidence confirming this. A 2010 survey of college-aged women, for example, found that 84 percent have fantasized about same-sex encounters or have had a same-sex . And in a study by Meredith Chivers female participants (irrespective of the they identified with) became aroused in response to all types of stimuli — from straight and lesbian porn to videos of copulating bonobos.

By contrast, men’s sexuality is still seen as less flexible. Only 51 percent of the aforementioned college women's male peers reported ever having a same-sex attraction or . And in Chivers' study, men who identified as straight were less likely to become aroused in response to that didn't correspond with their explicitly stated preferences. Researchers haven’t quite agreed on whether this is evolutionarily ingrained, or whether social stigma and traditional gender-based roles shape men’s expression and experience of desire.

Adding to this complicated picture is a recent study by researchers at Wayne State University and Western Illinois University, who planted themselves outside bars in a “Midwestern town in the United States” to recruit 51 men and 32 women for an experiment on sexual willingness.

The first step of the study was determining whether interested participants were sober enough to consent — to the study, that is. Sobriety was determined by a few coordination tests, similar to what a campus security official gives to apparently intoxicated students (such as rubbing your belly while patting your head without issue) and the ability to remember the researcher’s name and major after he or she stated it to the participant.

After proving themselves cognizant enough, participants were shown a brief PowerPoint presentation depicting an attractive young man or woman alone in a bar, chatting up the bartender. (Thirty-two percent of males and 23 percent of females saw an attractive young male; 29 percent of males and 16 percent of females saw an attractive female.) Some slides in the presentation had an audio component narrating a typical night out — “You walk into a bar. You sit down at an open seat at the bar…” — and describing the attractive other in the photos as stating to the bartender that he or she “wanted to see where the night would lead.”

Participants were then briefly surveyed about how likely they might be to do the following: a) buy the individual depicted in the PowerPoint presentation a drink; b) knock back a few drinks with the person; c) go home with the man or woman; d) spend the night; or e) sleep with this individual.

Then they were asked about their sexual orientation, assigned sex (e. ., male or female), age, student status, and recent consumption of .

Concurrent with previous research — such as a famous experiment conducted by Clark and Hatfield in 1989 that found women to be markedly less willing to go to bed with strangers than men are — female research participants in this study were, overall, less willing than male counterparts to engage in any sexual activities with the fictitious person seated at the bar. That reluctance decreased, however, with each successive drink female participants consumed.

Not so surprising, right? (In case you haven’t replicated this finding yourself, alcohol consumption has been proven to make us find more attractive those on whom we might not “swipe right” in a more sober state.) What was intriguing about participants’ willingness to hook up with a stranger was the difference along male and female lines: Women’s interest in hooking up with the fictitious individual at the bar increased with each drink regardless of that individual’s — despite the fact that all of the women in this study identified as heterosexual.

By contrast, men’s interest in hooking up with fictitious others remained stable with each drink when that fictitious other was a female. (In other words, alcohol had an insignificant effect upon a male’s willingness to sleep with a woman. They wanted to do so just as eagerly, regardless of their sobriety level.) Men’s willingness to experiment with another male sitting at the bar, however, was responsive to alcohol: The more the men in the study drank, the more open they became to having some type of sexual encounter with a man. Keep in mind that, like the women in this study, every male participant had identified as heterosexual.

The researchers believe that alcohol may loosen the constraints some men place on themselves that, when sober, enable them to to the sexual scripts they associate with traditional masculinity.

Such a propensity to explore options outside the straight and narrow may also increase over time; other research suggests that men’s attraction to same-sex partners rises with age. (Interestingly, the study observing this trend also found that women’s sexual interest in same-sex partners decreases with age, albeit only slightly.)

The takeaway of this study: Men’s sexuality isn’t necessarily as rigid as we may think. Nor does one’s stated sexual orientation determine or fix who and what one is attracted to, especially when alcohol is involved.