Research on bisexuality is sparse, but a few intrepid scientists have tried to get data by wiring up a group of gay, bisexual and straight men to a machine that monitored their arousal when exposed to erotic images of men and women.
The researchers found that, while some of their subjects called themselves bisexual, their male anatomy showed a notable preference for one sex or the other. That led to headlines proclaiming that bisexual men don't exist.
But such a proclamation would seem to depend on how you define bisexual. Does a person have to be absolutely equally attracted to both sexes? If you like both but prefer one, do you qualify? Scientists don't know. What they do know from tracking the spread of HIV is that
a number of men who have sex with men also have sex with women. A report from the Centers for Disease Control notes that 13 percent of white men who reported sex with other men also had sex with women. Among black men it was 34 percent, and among Hispanic men, 26 percent. Men can and do go both ways.
"This is something we don't quite understand," says Gerulf Rieger, a psychology graduate student at Northwestern University and lead author of the study. Rieger, who told me he's gay, said he, too, is a bit
baffled by the way other gay men manage to marry women.
In his study, he didn't see evidence for "bisexual arousal" among the 101 paid volunteers, recruited using alternative weeklies and gay publications. Of those, 38 identified themselves as gay, 33 as bisexual and 30 as straight. The researchers showed the men short films: one with two women having sex, one with two men having sex. They used lesbian sex because previous research showed it is more exciting to heterosexual men than male-female pornography.