From Undecided to Scientifically Proven Sexual Fluidity
Twenty years ago, this fluidity would have been interpreted as "undecided", "it's just a phase", or "closeted lesbian". (A lot of this stigma is still applied to bisexuals, by the way, but that's another topic.) However, research in sexual fluidity published in the last 10 years or so has changed the way sex scientists, at least, consider sexual orientation.
This discovery, however, causes problems. If gay rights are based on the fact that we can't choose our orientation, then the possibility of fluidity can work against them. To solve this issue, scientists separate two things: sexual orientation and sexual orientation identity. Sexual orientation is generally stable across a person's life, mostly because scientists believe it is biological in origin. Yet sexual orientation identity, or how we name our sexual desires, attractions, and behaviors, is socially determined. That makes it much more flexible.
As my own experience shows, sexual orientation identity can, and often does, change, especially for women. The fact that I came back to my original orientation doesn't mean that the changes were meaningless. In fact, with each change of identity, I acted in ways that heterosexual, pansexual, and bisexual people are "supposed" to behave. My innate orientation, or who I'm attracted to, never changed; but how I approached relationships with people of different genders definitely did.
Sexual Fluidity
The term "sexual fluidity" is generally attributed to developmental psychologist Lisa M. Diamond. A professor of psychology and gender studies at the University of Utah, she published a very influential book in 2009: "Sexual Fluidity: Understanding Women's Love and Desire." This book followed a group of women over 10 years. Diamond contacted them at regular intervals and asked them about their relationships, sexual orientation and sexual identity. She discovered that many of her participants changed their orientation identity throughout the study, even though their attraction didn't change as much.
