Call it a trend in two directions: Hollywood's It crew, from Charlize Theron to Billy Crudup to Liam Neeson to Colin Farrell, suddenly are all exploring Gore Vidal's famous pronouncement that "everyone is bisexual."

Perhaps no other current movie explores bisexuality with such dispassionate interest than does the biopic "Kinsey," which opens in Washington on Nov. 19 and stars Neeson as the zoologist with a clinical fixation on all things sexual: Two men share a room in a hotel. It's a business trip; they are colleagues; twin beds divide them. The older man talks on the phone to his wife while the other man, a much younger man, drops his trousers. He doesn't bother to cover up. He is young; he is beautiful; why should he? Through the telephone wires, the wife sounds strained, worried. Perhaps she senses what will come next. She has reason to worry. With a click of the phone, the men sit staring at each other from across the twin beds, indulging in a little verbal foreplay: Where are you on the gay-straight meter? Somewhere in the middle, they both admit. Surely there's nothing wrong with that, they murmur. They reach toward each other, and with a great, bruising kiss, they consummate the attraction that has been building between them.

Or how about this scene from "Stage Beauty," which opened this month, starring Crudup and Claire Danes: Two men wrestle about on a bed, believing that they are alone. One is tall and mustachioed; the other shorter and prettier. The tall one places a long blond wig on the pretty one. They make love as a woman watches in the shadows, in tears. Later the woman will sleep with the pretty man, and they will play with all sorts of possibilities. But in the end, she will want to know this: Are you a man or a woman? "I don't know," he tells her.

Or this one, from "Head in the Clouds," also released this month, with Theron and Penelope Cruz: Two women, both beautiful, one a blonde, one a brunette, kiss. She loves her; and she loves her; but one of the shes also loves him, a him who looks on with -- detachment? jealousy? arousal? -- as the blonde bites the brunette's lush lips, drawing blood.

No longer relegated to the outskirts of lower-than-low budget indie flicks, big-ticket films this year are matter-of-factly, with minimal judgment, exploring characters who are not either/or, but either and or, men and women who flit between men and women and women and men. There's almost always a love triangle involved, the better with which to juxtapose the conflict of choice and desire.

The matter-of-factness is the key element here. In the past, cinematic bisexuality was frequently a shorthand for unrepentant decadence, a world where anything goes, as in Bob Fosse's "Cabaret" (1972), where the sexually ambiguous emcee, played by Joel Grey, extols the virtues of "two for one" love: "We switch partners daily / To play as we please / Twosies beats onesies / But nothing beats threes." In "Cabaret," bisexuality is also an easy symbol for moral confusion; the character of Brian (Michael York), against the backdrop of Hitler's prewar Berlin, is seduced both by Sally Bowles and rich playboy Max.

York wasn't the only confused one. There was Marlon Brando in "Reflections in a Golden Eye," (1967) playing a man married to Elizabeth Taylor but lusting after Robert Forster. In 2003 Oscar darling "The Hours," each of its trio of female characters -- Nicole Kidman, Julianne Moore and Meryl Streep (she plays a lesbian mom who has conflicted feelings for a gay man) -- in a moment of emotional perturbation, suddenly grabs a woman and kisses her.

Then there are the vampire movies. Marjorie Garber, author of "Vice Versa: Bisexuality and the Eroticism of Everyday Life," notes the big role of vampires in the canon of bisexual flicks. Indeed, vampires in cinema are seemingly always bisexual, rapacious creatures who lust after beautiful victims with precious little regard for gender: Tom Cruise as the coolly elegant Lestat, pining over Brad Pitt and a prepubescent Kirsten Dunst in 1994's "Interview With the Vampire." David Bowie and Susan Sarandon taking on Catherine Deneuve in 1983's "The Hunger." The seductive sirens in "Bram Stoker's Dracula" (1992) munching on Keanu Reeves as Gary Oldman has a hissy fit because -- damn it! -- he'd saved Reeves for himself. And let us not forget Tim Curry's transsexual Transylvanian in "The Rocky Horror Picture Show," who takes malicious glee in seducing anyone and everyone who strays his way.

Also popular in film: the female bisexual as titillating arm candy, the embodiment of the two-is-better-than-one philosophy endorsed by many a heterosexual male. To that end, we have Sharon Stone's crotch-revealing switch-hitter in "Basic Instinct" (1992), who never met a switchblade she didn't want to use.

But with the increasing popularity of indie flicks, things changed and the stereotypes softened. Perhaps it was Kevin Smith's "Chasing Amy," in which Ben Affleck plays a cartoonist who falls in love with Joey Lauren Adams's character, a lesbian with a past filled with male and female lovers. Or "Kissing Jessica Stein," a comedy widely hailed as a breakthrough film for lesbians, which was actually about two bisexual women who meet cute, get together (after a protracted courtship), break up and end up settling down with other people. One ends up with a girl; the other, a boy.

"Frida," the biopic about the acclaimed Mexican artist Frida Kahlo, gave us the beauteous Salma Hayek with a mustache and a limp, hitting on men and women alike, particularly when the women were her husband Diego Rivera's extramarital lovers. The film portrayed her bisexuality as a game of sexual one-upwomanship, as in one potent scene, where a Rivera mistress made it quite clear that she preferred his wife's feminine touch.

Today, we've got male actors known for their macho appeal signing up for sexually ambidextrous roles. Aside from Crudup and Neeson, this summer brought us Farrell in "A Home at the End of the World." In the movie, a meditation on the nature of love, Farrell's character, the sweet-natured Bobby, is bisexual. Or perhaps he's omnisexual. He's so needy, his need for love so great, that it transcends sexual orientation. Like the stereotypical notion of women, he uses sex to get love. (And next month, we'll see Farrell playing "Alexander," the great man notorious for his attractions for both men and women.)

In a year marked by a scandal involving a bisexual governor and the hoopla surrounding a controversial book about bisexual black men ("On the Down Low," by J.L. King), do these films reflect a growing maturity about sexuality and all its complexities? Or an acceptance in Alfred C. Kinsey's notion that we're all basically bisexual, to one degree or another? Could be. But more than likely we can chalk it up as just another example of the famously capricious whims of Hollywood execs.

Swinging both ways: Clockwise from above, Penelope Cruz and Charlize Theron in "Head in the Clouds"; Ben Chaplin and Billy Crudup in "Stage Beauty"; Liam Neeson in the title role of "Kinsey"; and Colin Farrell in "A Home at the End of the World."