Pop culture loves the recreational lesbian -- the woman who dabbles but doesn't stay the course.
Lesbian turncoat Anne Heche left comedian Ellen DeGeneres for a man. Lush-lipped Angelina Jolie last week swore off former S&M mates and girlfriends in deference to her relationship with the uber-masculine Brad Pitt.
And Britney Spears, of the televised Madonna kiss, is now the subject of tabloid rumors for reputed dalliances with female porn stars and loyal personal assistant Shannon Funk.
The stars who flaunt their so-called lesbian status then change their minds may make it difficult for a new generation of young women who reject the dogmatic definitions of sexuality.
Young bisexual women face urban labels like "hasbien" and "Bug" (bisexual until graduation), not to mention the giddy voyeurism of male fantasies and the ridicule of their lesbian sisters.
For many of today's women in their late teens and 20s, openness to intimate physical relationships with either gender has become a way of life, rather than an "experiment." This relatively new phenomenon is likely a product of a generation unconcerned with labels.
"These young women see sexuality as a fluid thing," said National Gay and Lesbian Task Force spokeswoman Roberta Sklar. "It's not just between your legs."
"These relationships are physical, emotional and intellectual, and the boundaries are not hard set," she said.
Although there are no hard data on the numbers, Sklar said a growing number of young women have a "more flexible view" of their sexual partners, and their early choices of gender may not be a "fixed path."
"I know a woman who had relationships of depth with members of both sexes," said Sklar. "She didn't put a tag on what her sexuality identity was. Recently, I saw her at her wedding to a young, lovely man. In no way does she deny her history or say she has found her true sexuality. It was all her true sexuality."
Such is the case with Emma, now a 26-year-old Philadelphia law student who is in a serious relationship with her boyfriend of 18 months. But at 19, she had "come out" as a lesbian and had a five-year romance with a woman.
Emma said she was attracted to women in high school, but the topic was still taboo and she was afraid that confiding in friends would make them uncomfortable. When she reached college, she acknowledged her sexuality and fell in love with a woman.
"It was a difficult process, but once I was out and gay, I thought I would never date men again," she said. "But then we broke up, and I started dating a man. It was really strange and I was surprised. It's not what I expected at all."
Today some people trivialize her experience, saying, "You were young and stupid and didn't know what you were doing."
But Emma said being gay has been a powerful part of her identity, and the non-gay community is quick to point fingers. She also finds it difficult to maintain ties to the lesbian community, which is equally judgmental.
"It sounds like being gay was just an experimental phase," Emma said. "But that relationship was significant, and I might do it again."
When women exploit the shock value of bisexuality, they discount deep, loving relationships, she said. The sensational headlines about Britney Spears, who was born the same year as Emma, may only reinforce anti-gay stereotypes.
"I can't say what her sexual preferences are," said Emma. "You go into a bar and see girls making out with girls just to get the guys excited. But that is different from the women who fall in love with other women and take their relationships seriously."
Often it is in the enlightened college cocoon where women discover their sexuality, said Kaaren Williamsen-Garvey, director of the Gender and Sexuality Center at Carleton College in Minnesota.
"Identity politics are alive and well on college campuses," she said. In the 1990s, women used to joke about "lesbian until graduation," but now students are less judgmental and try to avoid the inevitable labels.
"In college it's normal for kids to push boundaries and roles and play around with questions of sexuality and gender," Williamsen-Garvey said. "But bisexuality is rooted in a culture based on two sexes and doesn't account for transgender, so many don't like the term. It's inherently complicated."
"Sexuality is not black and white, it's along a spectrum," said Williamsen-Garvey. "Sometimes it appears that students flirt with bisexuality and retreat. When they leave college the feelings and desires may still be there, but then they couple up."
Searching for a clear orientation after college, women usually end up identifying as lesbians or heterosexuals rather than continuing with a bisexual identity, she said.
"It's hard to maintain bisexual identity without a community [of support]."
Is it possible that seeing the the stars' same sex dalliances splashed on tabloid covers could actually help ease sexual taboos?
Bisexuality is really not a new concept, but today's social acceptance has allowed women to express their sexuality more openly, according to NGLTF's Sklar.
And the stars of today aren't necessarily bisexual trailblazers. Historians and feminists have analyzed relationships like those of Eleanor Roosevelt and others who had husbands as well as deep friendships with women.
After the anguish of her husband's affair with Lucy Mercer, Eleanor Roosevelt may have had two erotic relationships -- one with Earl Miller, a New York state trooper who became her body guard, and another with reporter Lorena Hickok, according to a biography written by Blanche Wiesen Cook.
"There is less taboo now in intimacy between the sexes," said Sklar. "But it's puzzling to me if it was always going on, or if it's now part of a post-feminist revolution."
"When I was younger and went to college, women were close to one another, but I look at my teenage daughter today and see a tremendous closeness between girls that does not translate into sexual intimacy," said Sklar.
"But," she added, "we are seeing something out there that is different than what we have seen before."