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Allen Rosenthal

Allen Rosenthal is a senior researcher at Northwestern University in Evanston. He led a major 2011 study on bisexuality.


What would you like people to know about your study?

The most important part of our study is that at least some men who identify as bisexual have the same kind of orientation that we would expect a man to mean when he says that he’s straight or gay. Prior to this I think that a lot of people kind of bought into the stereotype that bisexual men are somehow self-deluded gay men or extremely open-minded straight men. And while there certainly may be bisexual identified men who fall into those categories there are also bisexual men who experience strong attractions to men and women, which would be the common understanding of the term.

Weren’t there prior studies that doubted the existence of bisexuality in men?

Earlier studies that looked at the sexual arousal patterns of bisexual men had found that on average they had arousal patterns that looked like gay men, which is to say that they only got strongly aroused with video showing two men, and they didn’t get aroused at all or very much with video showing two women. There were some weaknesses in those earlier studies however. So, for example, a lot of the bisexual men were recruited through gay student unions, gay magazines. Additionally, there weren’t any inclusion criteria that were used to make sure that the men who were coming into these studies had adequate romantic or sexual histories with members of both sexes.

Where did you find subjects to participate in your study?

Initially, we were looking for bisexual participants in a room of Craigslist for gay men who were looking for male sexual partners and we weren’t having much luck. It was then that I discovered a room on Craigslist called the “Casual Encounters” room. There were different sub-rooms within this where people place personal wanted ads for either a date or a sexual encounter. In particular, I found a room called the MW4M room. This is a room of ads placed by a man and a woman for a man. And in this room, heterosexual couples place ads where they are seeking a man to come join them in a 3-some. And we reasoned that men perusing these ads, in particular, would be likely to have strong sexual interest in both men and women.

What were the requirements for inclusion?

In our study, we required that our bisexual participants had to have had two sexual partners of each sex and at least one romantic relationship of at least three months length with one man and with one woman. The bisexual men in our study did get strongly aroused to videos of two women as well as videos of two men, establishing that there is, in fact, a bisexual orientation among men.

How did you measure sexual attraction?

The technique that we use in our lab is called penile plethysmography. The root of the word plethysmography means to record changes. And, so what it involves, a man wears a small gauge that looks just like this (Rosenthal points to device in video) around the base of his penis and it measures increases in the girth of his penis, usually while he’s watching erotic video stimuli. The important stimuli we show are two men having sex and videos of two women having sex, and that’s because if a man experiences arousal to those kind of videos you know that he is getting aroused to either men or women respectively. We also show heterosexual sex scenes, but because there is something in it for everyone, usually men’s arousal to that doesn’t allow us to differentiate different kinds of men.

How did your study subjects react to participating in the study?

One thing that we noticed is that a lot of the bisexual participants as they came out of the experiment would tell us how glad they were that we were doing this kind of research and that they wanted to have their orientation and identity validated by the scientific community. Especially after a number of earlier studies had concluded that virtually all bisexual men don’t have bisexual arousal patterns.