Ellen DeGeneres is leading a fundamental change in the way we buy clothing

Ellen DeGeneres's clothing line, ED, is notable - and not just because it's another fashion line by a celebrity.

The line offers clothing with gender neutral lines for women, highlighting the notion that being a girl is not analogous with dressing girly.

DeGeneres's collaboration with GapKids, GapKids x ED, with the corresponding hashtag "#heyworld," launched earlier this summer. It zeroed in on giving girls the option to be who they want to be, not what clothing stores dictate they should be. This was very important to DeGeneres.

"When I was growing up I didn't have a lot of choices, as most kids don't," the comedian and businesswoman said to Mashable this summer, "It really starts when you're young. It starts when you're able to express yourself."

DeGeneres's clothing line has no dresses, but there are tailored jackets, polos, and clean, neat lines.

Gender neutral clothing is becoming a critical niche in the apparel industry, and the importance is twofold: one, retailers are recognizing that women and men need not be confined to traditional gender roles, and two, it shows that retailers are responding to a society that is accepting of those with gender fluidity.

Acne Studios - the retailer that launched the short-sleeved suit for men - has demonstrated androgyny as its hallmark. In fact, in a recent ad, the company used a twelve year old boy as a model. Not everybody responded positively to this.

"Acne confirms: fashion ideal woman is a 12-year-old boy," wrote Leann Duggan of Yahoo Style, missing the point that the campaign was about gender fluidity, not about telling women they should look like little boys. 

"Sometimes, you know in your heart of hearts that something terrible is true. And yet, you still reserve the right to be annoyed when it's actually confirmed before your eyes," Duggan wrote, proving that not everybody might be ready for a gender fluid fashion landscape.

But non-gendered clothing  isn't a new, groundbreaking phenomeon. In fact, as Marc Bain of Quartz pointed out, it's been around for centuries - even the ancient Romans wore gender neutral tunics!

Dr. Jo Paoletti told Bain that she believes the recent surge in non-gendered clothing is "unfinished business from the 1970s." 

"There were a lot of questions raised by feminism, the Civil Rights movement, the gay rights movement about gender roles, and the extent to which individuals should follow gender roles," she said to Bain. "And part of that is going to be the way you look."

It also helps that gender fluidity has been in pop culture's vernacular as of late, especially with sports star (and Kardashian patriarch) Caitlyn Jenner.

Further, unisex clothing now has an elevated meaning. Browsing Babies 'R' Us's selection of gender neutral baby clothes evokes not only the notion of a budget-savvy family awaiting a newborn, but a family that doesn't wish to impose a gender upon its child. After all, gender is not mandated at birth.

As society becomes more adjusted to the idea that gender is far more fluid and that it can be expressed via clothing, the fashion industry has responded. There are a number of smaller designers and brands latching onto the unisex sector, and high fashion has responded, too. Gucci showed off feminine male designs this summer at Milan Fashion Week.

This summer, Ruth La Ferla of The New York Times called it "The Great Gender Blur." 

"That crossover was especially apparent in men's collections quietly venturing onto women's turf, that move an opportune nod to those progressive young urban women who have long been among the most avid consumers of luxury men's wear with a funky street-wear provenance," La Ferla wrote.

"The whole perception of sexual orientation is being challenged by the millennials," Lucie Greene worldwide director of JWT Intelligence, said to the Times. "Among the cohort of 12-to-19-year-olds defining Generation Z, ... the lines between male and female have become increasingly blurred, and we're seeing that reflected in the collections this week [Milan Fashion Week.]

Other people in the retail space anticipate this sector to continue to evolve - it's not a trend; it's simply fashion evolving with society.

"The definition of gender has changed a lot, and so have expectations," Emma McIlroy, the co-founder of the gender neutral store WildFang in Portland, said to Oregon Live.

In the future, she expects clothing identified by a binary gender system to be nonexistent. "They're not going to be merchandized by men's and women's," she said.