Gender fluidity, when gender expression shifts between masculine and feminine, can be displayed in how we dress, express and describe ourselves.
Everyone's gender exists on a spectrum, according to Dot Brauer, director of the LGBTQA Center at the University of Vermont. Progressive gender expression is the norm for the university, which offers gender-neutral bathrooms and allows students to use their preferred names.
"If you imagine the spectrum and imagine the most feminine expression you have ever seen and most masculine you have ever seen and just sort of imagine where you are on that," Brauer said.
Brauer, who identifies as gender-queer and prefers the pronoun "they," said gender identification is about what feels right for the person.
Information is fluid
"In my generation, all the information that came to me was filtered through some very sort of limited perspectives and limiting languages. So for example, if I was going to find out about gender, I was going to find out about it through health class in a curriculum that was set by the Board of Education," Brauer said.
Since millennials grew up with the Internet, members of that generation can easily find information on topics like gender expression, added Brauer, 58.
Lee Luxion, who is 26 and also prefers the pronoun "they," might wake up as a man or as a woman, sometimes as both and sometimes as neither.
"How I express it is usually how I dress, how I do my hair. But then my mannerisms change. The way I speak might change a little, too," Luxion said.
Luxion agreed that the Internet, along with the emergence of gender-fluid celebrities such as "Orange Is the New Black's" Ruby Rose
, has made millennials more comfortable with expressing their gender.
"There shouldn't be a sense of what's normal and what is not," Luxion said. "And (with) more representation of transgender or gender-fluid or non-binary individuals, the more likely it is that we are going to feel safe to also be that publicly."
There are lots of misconceptions about gender fluidity, according to those in the community. Being gender-fluid doesn't determine a person's sexual preference.
Gender fluidity isn't the equivalent of transgenderism, in which a person's gender identity is different from the one assigned at birth.
Luxion balks at the idea that gender fluidity isn't a valid gender, a refrain they've heard time and again.
"Gender fluidity is much more than saying, 'oh, I want to play up the femininity traits that I have' or that 'I want to play up the masculine traits that I have.' It's an actual physical, mental and, for me, emotional shift in how I interact with the world."
More than just appearance
Theresa "TDo" Do, a 37-year-old San Francisco native, was born and raised female but never felt that way. She appears androgynous with a short haircut and expresses her gender fluidity in how she behaves.
In situations when Do feels challenged, she said, she feels more masculine and expresses herself in that way.
"The tone of my voice does change. It comes a little bit more forward. My voice drops a bit," she said. "I have been told that I walk really masculine, and I puff my chest out when I'm walking."
When she feels like she is in a safer place, she becomes more feminine.
"My voice gets a little higher. I drop my shoulders. I allow people to just get closer to me emotionally and in a physical way," Do said. "For me in particular, when I am in touch with my feminine side, I feel soft."
Brauer said others' perceptions and an individual's interpretation of their own gender play a part in how gender is conveyed.
"There's this constant exchange going on. ... Identity is this weird thing that exists between us people. It's like this perception, thought space, between us and other people," they said.
Thomas Webb, 33, identifies as gender-fluid and feels masculine "two-thirds" of the time. Webb's gender-fluid expression alternates from masculine to feminine with how they dress, from suits to skirts.
"When I was in high school, I don't remember words like that ever existing. I didn't learn about the word 'gender-queer' until my early 20s. I was using terms like 'cross-dresser' or 'transvestite' to describe myself, because that was all that I was aware of at the time," t