2015 will be remembered as a turbulent year in which the most unorthodox and disruptive presidential campaign in history turned tradition on its head. Perhaps just as significantly, it will also be remembered for being what writer Nico Lang called the year of the gender fluidity revolution. It was a year in which transgender issues gained national attention via the very public stories of celebrities such as Caitlyn Jenner, whose transition from male to female was splashed on a magazine cover, and the more pedestrian but no less controversial battles over the law restricting transgender bathroom access in North Carolina.

Suffice it to say that in 2015, a tradition of invisibility was broken in the U.S., and what had been a transgender moment made the leap to a civil rights and human rights movement in the tradition of racial justice and other social justice movements that are still under way. At UCLA and campuses across the country, that movement has also brought science to the fore, in questions about the biology of sexuality and how it relates to gender identity.

No Clear-Cut Answers

While more is understood about both, the science is not definitive. What’s clear is that gender fluidity is just that — fluid — with many factors that shape identity. Both science and the social movement are arguing for something Americans have always been uncomfortable with: no clear-cut answers. In its comprehensive look at the new field of sex and gender biology in the spring of 2015, UCLA Health’s U Magazine noted that “pitted against familiar ‘black-or-white’ stereotypes of what it means to be male or female, masculine or feminine, society struggles to accept what lies in between.”

Still, the subject is now being addressed in a big and unprecedented way. Non-binary, gender-nonconforming, transgender, intersex — the labels are cohering into a single demographic, popularizing the idea that gender identity is complicated and is pitched somewhere among biology, environment and personal choice.

Limitations of Science

The boundaries of what is male and female that have been challenged by gay and lesbian activism are now being challenged in an even deeper way by gender ID activism. This new challenge says that it is up to individuals — not society, or even science — to determine who they are or are not. To try to mainstream such a middle ground, especially around something so foundational and traditionally binary as gender, feels nothing less than revolutionary, especially in polarized America.

“The truth is always in the middle,” says Eric Vilain, former UCLA geneticist and expert on intersex biology and development. Like so many working and writing in the field, Vilain has become controversial in the emerging science of gender identity. “I’m in the middle. But it’s not always a popular place to be,” he says.

The research supports the notion that we don’t have enough science to know if gender ID is largely scientific or not. In 2014, a team led by a psychiatrist at the Medical University of Vienna published a report acknowledging some brain “cross-link” patterns distinct to gender identities in the brain tissue known as “white matter”:

“Transgender persons, as well as female and male control subjects, were examined by way of diffusion-based magnetic resonance tomography (MRT). The examination revealed significant differences in the microstructure of the brain connections between male and female control subjects. Transgender persons took up a middle position between both genders.”

Politics, of course, also enters the fray. For example, there’s a hotly debated study titled “Sexuality and Gender” that was published in a conservative bioethics journal. The study was authored by Paul R. McHugh and Lawrence S. Mayer. McHugh is an academic known for shutting down the sex reassignment clinic at Johns Hopkins Hospital almost 40 years ago. The two flat-out reject the idea of any scientific basis for the notion that gender identity and sexual orientation are fixed or innate. In response, an op-ed in The Baltimore Sun authored by several Johns Hopkins faculty members noted that the study was not subjected to rigorous peer review. “It purports to detail the science of this area, but it falls short of being a comprehensive review,” they wrote.

Sidestepping Identity Labels

For Jody Herman, a scholar of public policy at UCLA’s Williams Institute, the influential think tank focusing on LGBT research and public policy, the question of biology is somewhat beside the point. The institute is currently conducting a study of randomly selected transgender people, the first study of its kind. Random selection is the gold standard of demographic studies: It acknowledges the significance of a population and helps establish data by which to track its health and status and build public policy. But how to even identify a population that’s so fluid, that goes by so many labels?

Herman says it was relatively simple. Borrowing from an HIV survey pioneered in the ’90s by the Transgender Health Advocacy Coalition in Philadelphia and used by the Centers for Disease Control and Prevention since 2011, the new study asks participants two questions: the sex they were assigned at birth and the gender they identify with now. If the answers don’t match, the person is determined to be transgender.

“This is the measure that we think will capture the trans population,” says Herman. “You do have to be careful measuring identity. We live in a time in which gender terms are fluid — non-binary, gender-nonconforming, trans people who identify not as trans, but as male or female — so we as researchers don’t rely on a long list of identity labels. We have to be consistent to map our trajectory.”

Marginalized and Vulnerable

Perhaps not surprisingly, what has been measured by more narrow and less scientific methods, such as surveys and samples, has painted a troubling picture of the transgender population. In 2015, a groundbreaking study done by the National Center for Transgender Equality found that trans people have high rates of poverty (29%), suicide attempts (40%), psychological distress (39%) and harassment in public bathrooms. In fact, 8% of trans people report suffering kidney problems from avoiding using bathrooms. “Lots of bullying takes place in the radius of the bathroom,” says the Williams Institute’s director of international programs, Andrew Park.

Despite the sexy images of celebrities like Caitlyn Jenner, Miley Cyrus and gender-fluid Ruby Rose of Orange Is the New Black, trans people are emerging as one of the most marginalized and vulnerable groups in America. As there’s a gap between science and social movement, there is also a gap between public opinion of transgenderism and the daily realities of transgender people.

That gap feels similar to the old gap of race. Everyone claims to decry racism, yet black people still suffer the effects of discrimination every day. UCLA sociologist Rogers Brubaker was struck by how the Caitlyn Jenner moment in 2015 coincided with the brief but intense scandal surrounding Rachel Dolezal, the NAACP leader in Spokane, Wash., who had long presented herself as black but was outed by her parents as white. Brubaker wrote a book, Trans: Gender and Race in an Age of Unsettled Identities, examining how the transgender experience — not just movement from one category to another, but the staking out of new positions between and beyond existing categories — can help us think about the fluidity of racial and ethnic identities in new ways. Brubaker admits the comparison isn’t perfect; the idea that a person without African ancestry might “feel” black is seen as ludicrous, whereas a biological male who identifies as a woman is taken seriously. Gender identity is increasingly seen as up to the individual to determine, while racial identity is not, since it depends on one’s ancestry.

“I would distinguish between personal and categorical identity,” he says. “All of us want to be recognized as individuals, and as human beings, independently of how we are labeled and categorized in gender, ethnoracial, religious or any other terms.” He thinks most people probably continue to experience their sex/gender and ethnoracial identities as given and stable. But he argues that a growing minority experience those identities as open to choice and change, though in differing ways and to differing degrees.

In this regard, the U.S. is playing catch-up to the rest of the world. “On the global level, the issues of gender ID are moving more quickly than other LGBT issues,” notes Park, who co-authored a global survey on attitudes toward trans people that was conducted in 23 countries and published in December 2016. “In other countries, there is a long history of trans presence and acceptance. For example, in India they’re part of Hindu scriptures. It’s part of the reason that India, Nepal and Pakistan recognize a third gender, an ‘other.’ We don’t think of a heavily Muslim country like Pakistan as progressive in terms of gender, but there’s a recognized and historic place for TG people, going back to the court of Mohammed.”

Park says, “Things are moving faster than we anticipated. … Overall, our survey showed very high levels of support for gender ID that we didn’t expect. A lot of people felt discomfort with gender gray areas, but still supported trans rights.”

In the end, says Jody Herman, “gender ID can’t be manipulated in any way — that’s the reality, that’s the point. People can’t be swayed from their ID. That’s what we focus on.”