Sexual Identity is Fluid

One of the most meaningful things a counselor can say is: You get to define who you are, even if that definition changes.

In therapy, we use words like sexual orientation and sexual identity to understand how someone experiences attraction and how they label or make meaning of that experience.

In real life, those terms are often tangled, fluid, and deeply personal. For some people, orientation feels fixed. For others, identity unfolds over time, often shaped by relationships, safety, grief, or healing.

This post breaks down what research says about sex differences and why it’s important to honor both science and story. As a person who loves knowledge, I've followed research on sexuality as a politically hot topic in mental health for the past 20+ years. As I was putting my article into ChatGPT -- yes my dear reader, as a mother of six children, a graduate student, a person on the brink of validating my religious and spiritual trauma assessmnent, and a person getting ready to open a counseling center through my nonprofit, I'm busy! I'm too busy to write every word of every article I post; I use AI to write the research breakdowns and citations --

Sorry for the long aside. As I was putting what I had written and what I wanted filled out into ChatGPT, we got into an argument as politcally correct statements came spewing out of the algorithm. I found myself demanding: What does the research say - why are you ignoring the validated research? What about the study in Sweden? You contradicted yourself. Can you justify that statement in the research? What about that study that cut off in men's dating age before their twenties to prove they were bisexual? ..... For all of the societal unrest regarding the topic, the degree of ignorance about the science of sexuality is horrifying! Not all research is equal. Is it peer reviewed? Is it replicable? No? Then don't act like it's fact. I am a born skeptic. That being said, let's jump in.

Current Definitions from the APA dictionary: https://dictionary.apa.org

Gender - the socially constructed roles, behaviors, activities, and attributes that a given society considers appropriate for different genders. In a human context, the distinction between gender and sex reflects the usage of these terms. [I add] For example, there was a time in England that boys wearing pink was considered manly because men wore red. Today, boys wearing pink is considered effeminate in some societies. Girls shouldn't like fist fights. These are cultural ideals, nothing that actually defines a person's sex.

Sex/Sexual Identity: the purely biologically determined sexual status of an individual as male, female, or intersex.

Sexual Orientation - a person’s sexual and emotional attraction to another person and the behavior and/or social affiliation that may result from this attraction.

Women and Sexual Fluidity

Research over the past two decades has consistently shown that women’s sexual identity is more fluid than men’s. The most influential voice in this area is psychologist Lisa Diamond, who followed a group of women over 10 years. Many participants changed how they identified from heterosexual to lesbian, bisexual, queer, or unlabeled. But their core attractions didn’t always shift; it was often the relationships that sparked the change in self-description.

Some women who had only dated men before found themselves falling in love with a woman in midlife. Others left long-term heterosexual marriages and began same-sex relationships that felt more emotionally safe. These changes weren’t necessarily about "switching sides", they were about emotional intimacy, healing, and openness.

A large twin study in Sweden (Långström et al., 2010) supported this picture: for women, same-sex behavior had about 19% genetic influence and 17% shared environmental influence. That means context matters—attachment, trauma, safety, culture, and life stage can all influence identity expression.

Male Bisexuality - Yes, it Exists

Male sexual orientation tends to be more stable over time—but that doesn’t mean it’s less complex.

The same Swedish twin study found about 39% genetic influence in men’s same-sex behavior, with nearly zero impact from shared environment. For many men, orientation shows up early and remains fairly consistent throughout life. But societal pressure often blocks honest expression—especially for bisexual men, whose orientation has historically been questioned or erased.

That changed in 2012 with a landmark study by Rosenthal and colleagues. They found that some self-identified bisexual men did show distinct arousal patterns to both male and female stimuli. These findings corrected earlier studies that failed to account for relationship history and used flawed measures.

Identity and Culture Changes: As a Species, We Adapt.

Clinical language gives us tools to understand sexuality, but it should never override a person’s right to self-definition. What we call ourselves can change over time. The words available to us shift with culture, politics, and personal growth.

In the past, there were fewer labels—or more rigid ones. Today, there’s more room for people to say “I don’t know,” or “I changed,” or “I feel differently now.”

In my practice, I try not to fit people into boxes. I meet them where they are and walk with them toward understanding themselves on their own terms. The science is useful. But the story is theirs to tell.

References (APA 7)

Diamond, L. M. (2008). Sexual fluidity: Understanding women's love and desire. Harvard University Press.

Diamond, L. M. (2012). The desire disorder in research on sexual orientation in women: Contributions of dynamical systems theory. Archives of Sexual Behavior, 41(1), 73–83. https://doi.org/10.1007/s10508-012-0024-9

Diamond, L. M. (2020). Gender fluidity and nonbinary gender identities. In APA Handbook of Sexuality and Psychology.

Långström, N., Rahman, Q., Carlström, E., & Lichtenstein, P. (2010). Genetic and environmental effects on same-sex sexual behavior: A population study of twins in Sweden. Archives of Sexual Behavior, 39(1), 75–80. https://doi.org/10.1007/s10508-008-9386-1

Rosenthal, A. M., Sylva, D., Safron, A., & Bailey, J. M. (2012). The male bisexuality debate revisited: Some bisexual men have bisexual arousal patterns. Archives of Sexual Behavior, 41(1), 135–147. https://doi.org/10.1007/s10508-012-9918-6