There is a long-standing stereotype that women's sexuality is more fluid than that of men — also known as the "all woman are a little bisexual" theory. The thing that annoys me about this stereotype is that it plays into the (mostly male) fantasy that there is some secret code or enough alcohol that will convince otherwise comfortably straight women (who are obviously fooling themselves) to engage in sexual activity with other women, while comfortably straight men are just, you know, straight. Besides the fact that very little sexuality is black and white — witness my gay neighbor's ostensibly "straight" dates coming by late at night, or the occasional sexual propositions I get at gay clubs, for instance — I also feel that it plays into this idea that you can "choose" your sexuality, that sexuality is a Pick-Your-Own-Adventure game and that women will be inspired or can be convinced to pick otherwise, which is really condescending. And, so, it doesn't surprise me that either Salon or the New York Times articles about Dr. Meredith Chivers' research into human arousal get it wrong.
Chivers' research shows that women are more easily aroused than men (no, seriously, it does), except when it comes to looking at hot naked men doing non-sexual things. I think I can speak for a number of straight women here when I say that even the hottest naked guy can do bad-naked things and that, sometimes, a flaccid penis on even a hot guy jumping around isn't going to get my engine running. But women do get physiologically aroused by naked women bouncing around, all kinds of porn and even monkeys fucking. And, thus Salon and the New York Times declare us all a little bisexual. [Insert long sigh here]
Chivers does her best to point out that what one fantasizes about or gets randomly turned on by doesn't have anything to do with what you are actually interested in doing.
To conclude that women are bisexual on the basis of their sexual responding overlooks the complexity and multidimensionality of female sexuality.
Not that anyone cares, of course, because it's not as a good a story as us ladies are all one small push away from eating each other out with great gusto.
But if we all stopped and thought about it for a second, we all are aroused by things, or fantasize about things to get aroused, that have no actual interest for us sexually. I've had sex dreams about women, fantasized about group sex, public sex, the dirtiest of anonymous sex, sex in public places, sex with inappropriate people... none of which I've ever done or really made any effort to do in the last 14+ years of sex-having because they don't hold any real-world interest for me. I don't think that fantasies of having a threesome makes you a swinger, or that getting aroused watching monkeys fucking means that you're into bestiality, or that fantasizing about S&M makes you a closet submissive, and thus I don't think that getting aroused at the sight of women bouncing up and down (images, notably, that we're strongly culturally socialized to think of as sexy) makes an otherwise straight woman bisexual.
This might be a little nurture-over-nature for most people, but I would expect that in a culture that fetishizes the female form in so many ways and does not fetishize the male form in the same way women would naturally be more aroused by random naked women than random naked men because so much of sexuality is in your head anyway. And, in a culture in which the male homosexual taboo is so strong, I would equally expect that many, many men would not find images of hot naked guys sexy because male sexuality is not all in their dicks, either — it's in their heads as well, jostling around with their taboos. But maybe I'm just trying to justify my closet bisexuality. That's probably what the New York Times would tell me, just before the Grey Lady tried to stick her tongue in my mouth.