New study suggests bisexual men are neither gay nor straight

There is robust evidence that bisexual men exist, and they are physiologically aroused by both men and women, according to a new study.

Male bisexuality has sometimes been challenged, based on a popular assumption that men are either straight or gay, with nothing in between.  But that’s not true, according to the new study, in which scientists from Essex and the USA combined all available and previously published data. Specifically, they were able to reanalyse over 400 men’s penile responses to erotic videos of men and women. 

They found that male sexual orientation and arousal encompasses a range, from straight to bisexual to gay. Importantly, unlike in some of the previous small studies, there was clear evidence that bisexual men get strongly aroused by both men and women.

As Dr Gerulf Rieger, from the Department of Psychology at the University of Essex, and one of the senior authors of the study, explained: “It has always been clear that bisexual men exist in terms of self-identity and behaviour, but many, including myself, were sceptical about their ability to be sexually aroused to both men and women. Now, with this exceptional number of participants, we have clear proof of their bisexual arousal. This reshapes our entire understanding of male sexual orientation.” 

Dr Rieger’s scepticism stemmed from a previous small study he had done with Professor J. Michael Bailey of Northwestern University in 2005, and which found no evidence of bisexual arousal in men. This had led to a New York Times article “Straight, Gay or Lying?,” which dismayed many in the bisexual community. A further small study, by the same team, in 2011 confirmed the existence of bisexual arousal in men. 

The new reanalyses included data from both of those studies, and six others - affording much greater statistical power than data from any of the individual studies.  In combining all these data, researchers considered two measures. First, they evaluated whether erotic videos of women aroused bisexual men more than they aroused gay men, and whether erotic videos of men aroused bisexual men more than they aroused straight men.  Bisexual men were aroused more in both cases. 

Second, they examined the difference in each man’s arousal to women and men, to see if bisexual men would show less difference in arousal, compared to gay and straight men, to women and men.  Bisexual men indeed showed less difference in arousal to both sexes.

Lead author Jeremy Jabbour, a PhD candidate at Northwestern, remarked “Our results paint a powerful picture of male sexual orientation having gradients and nuance. Although I don’t think that bisexual men need research like this to validate or justify their lived experience to others, I’m hopeful that findings such as ours will continue to help the public see the many shades of grey that exist in human sexuality.”

John Sylla,  was one of the 13 authors of the new paper. He is a Los Angeles lawyer and Lecturer in Law at the University of Chicago, as well as being president of the American Institute of Bisexuality, a charity focused on bisexual research, education and community-building.

He said: “People who are purely straight or purely gay can tend to generalise their own experience and think all other people must be just one or the other. There are bisexually aroused men and women, even if for different reasons they choose to pass as just straight or gay.”

The new study is  published in the prestigious Proceedings of the National Academy of Sciences.