(CNN) For some people, gender is not just about being male or female; in fact, how one identifies can change every day or even every few hours.

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

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

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," they said.

Raising a gender-fluid child

Franki Davis, 14, identifies as gender-fluid demiboy and uses the "they" pronoun.

Demiboy means a person identifies partially as a man.

Franki has bright green hair and an androgynous, neutral appearance. Like any teenager, they like to go to concerts, take pictures and Skype with friends.

Franki discovered their gender identity during adolescence. And when they came out as demiboy, mom Kristen Shaw homeschooled Franki due to the anxiety they faced at school.

"My greatest concern was that they were going to be more isolated and the limited friendships they have socially," Shaw said.

Shaw said she would tell a parent of a child like hers to understand that it's important to let them grow.

"Before our children were born, what was most important was that we proclaimed that all we wanted was a healthy baby. And if we are lucky enough to have that, then we just take it from there. It's a one day at a time process. Our job is to be their life cheerleader and set them up for success," she said.

Opinion and intersectionality

Brauer writes in a paper titled "Gender: It's Complicated" that younger generations see identity through "the lens of intersectionality," which includes age, sex, location, socioeconomic class and other factors.

"I might be perceived as someone who has a female sex to be pretty masculine by the gender standards of femininity that exists" in the mid-Atlantic, Brauer said. "But here, in Vermont, the standards for gender and femininity are different. So, right here I would be seen not overly masculine and not overly feminine."

When Do is in the office, she said, she gets stares from clients when expressing her gender fluidity.

"In a business meeting, I might have to look a little bit harder to earn the respect of others," she said. And when she leaves the "San Francisco bubble," she feels more tension.

Webb, who lives in Southern California, said they haven't felt discriminated against because they stopped publicly wearing women's clothing and dressing androgynously. They said it was easier dressing as a man than a woman.

"People kind of confuse personality and gender. My personality isn't stereotypically feminine. So even when I'm wearing a skirt and everything, people just look at me as a dude in a skirt for better or worse. ... I don't think they treat me as they would a lot of the trans or other gender-fluid people who happen to act more feminine," Webb said.

For Luxion, telling someone their gender identity can lead to hurtful responses.

"When I get negative responses or people telling me that my gender is invalid or wrong, it's frustrating and it's hurtful, but really it's making me sad that people still aren't willing to take a step back," Luxion said. "It's not doing anyone harm. So I don't understand why they would be so opposed to it."