The exclusive 'or'
A group of psychologists say that their research indicates that there is no such thing as male bisexuality. From New York Times:
...a new study casts doubt on whether true bisexuality exists, at least 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.
By the 1990's, Newsweek had featured bisexuality on its cover, bisexuals had formed advocacy groups and television series like "Sex and the City" had begun exploring bisexual themes.
Yet researchers were unable to produce direct evidence of bisexual arousal patterns in men, said Dr. J. Michael Bailey, a professor of psychology at Northwestern and the new study's senior author.
A 1979 study of 30 men found that those who identified themselves as bisexuals were indistinguishable from homosexuals on measures of arousal. Studies of gay and bisexual men in the 1990's showed that the two groups reported similar numbers of male sexual partners and risky sexual encounters. And a 1994 survey by The Advocate, the gay-oriented newsmagazine, found that, before identifying themselves as gay, 40 percent of gay men had described themselves as bisexual.
About 1.5 percent of American women identify themselves bisexual. And bisexuality appears easier to demonstrate in the female sex. A study published last November by the same team of Canadian and American researchers, for example, found that most women who said they were bisexual showed arousal to men and to women.
Although only a small number of women identify themselves as bisexual, Dr. Bailey said, bisexual arousal may for them in fact be the norm.