This is interesting, similar to what I have written. The article questions the existence of (real) bisexuality in men.
The study, by a team of psychologists in Chicago and Toronto, lends support to those who have long been skeptical that bisexuality is a distinct and stable sexual orientation.
People who claim bisexuality, according to these critics, are usually homosexual, but are ambivalent about their homosexuality or simply closeted. "You're either gay, straight or lying," as some gay men have put it.
In the new study, a team of psychologists directly measured genital arousal patterns in response to images of men and women. The psychologists found that men who identified themselves as bisexual were in fact exclusively aroused by either one sex or the other, usually by other men.
The study is the largest of several small reports suggesting that the estimated 1.7 percent of men who identify themselves as bisexual show physical attraction patterns that differ substantially from their professed desires.
From what I understand, the article is correct insofar as we understand "bisexuals" to be those who are fully and evenly attracted to both sex. For the male gender, they are so rare as to be perhaps nonexistent. Yet, other studies, cross-cultural evidence, and I'm sure many personal anecdotes of which we are all aware, demonstrate the existence of many men, both on the "gay" side and "straight" side, having relations with both sexes.
If simply having "relations" with both sexes -- being able to perform and enjoy it -- makes one a "bisexual," then male bisexuals, far from being non-existent or extremely rare, are rather extremely common. You see we are dealing with different understandings of "bisexuality" here.
The article claims that most people who label themselves as "bi" are really one or the other, but mainly "gay." (The article doesn't mention this:) There are men who are predominantly homosexual, who are active with both sexes, and label themselves "bi." There are also men who are predominantly heterosexual who are active with both sexes; but they most likely label themselves "straight."
Like it or not, a social stigma still comes with the gay or bi label, and most people are loathe to put that label on themselves unless they honestly feel a need to come out and join the gay or bi community. So why would a guy who is predominately homosexual label himself "bi"? Perhaps to appear at least "half-normal." But a guy who is predominantly heterosexual with some marginal bisexual tendencies wouldn't ordinarily want the "stigma" of a "bi" label. Guys don't like having their manhood questioned, which like it or not, a "gay or bi" label does.
There are some exceptions...those predominately hetero guys, who would, for political reasons, embrace the bisexual label. Kurt Cobain comes to mind.
One unexplored implication of the article: It stated that many of those who label themselves as "bi" show little if any attraction to one of the genders, suggesting a disconnect between what they are and how they label themselves; but it didn't ask whether their behavior was somewhat consistent with how they labeled themselves. In other words, do these predominantly homosexually oriented men sleep with both sexes (even if they are a lot more active with men), as their label suggests?
Again, this is something about the "male" gender -- certainly not all of us, but a good deal of men: Some guys, it seems, can (forgive me for getting a little vulgar) "get it up" for anything, even inanimate objects. These might be men who are at the tail end of the bell curve (or maybe a good part of the right half) in terms of testosterone levels and the need for sexual release.
For such a guy, even if homosexual, he could perform heterosexually, and conversely, if heterosexual, could perform homosexually. This raises the question whether those men engaging in "situational" homosexuality or "situational" heterosexuality (which I'd estimate at least 1/3 of the gay or straight population can do) are really attracted in any meaningful way to what they are having sex with, or if it's just the ability to get it up for any object and perform that is in play.