A recent study conducted at the University of Utah (really? Utah? Oh well, it's written down, so it must be true) and reported on by USA Today followed 79 "nonheterosexual" women for ten years, beginning with their college years. OK, kinda creepy.
Anyway, over that ten-year period, one fifth (that's 20% for the mathematically challenged) decided that they were straight. Yet at the end of the ten years, half of those women had gone back to other women. The majority of women who claimed to be bisexual continued to be attracted to both men and women and alternated between the sexes (maybe sometimes at the same time...no, the report didn't say that, but come on, it had to happen a couple of times...don't rain on my parade).
So what does this tell us, other than men are pigs and women prefer the company of other women (two things that we already knew)? Well the research goes a long way toward dispelling the myth that young women who exhibit bisexual tendencies are either gay or they're just "engaging in a trendy experiment that they'll later abandon" (otherwise known as college). Some women are just authentically bisexual, like Angelina Jolie.
One final note, at the end of the study, 89% of the bisexual women studied were in a relationship (more than either the straight women or the lesbians) thus proving the saying that "being bisexual doubles your chances of a date on Saturday night."