In London last week, Selfridges, the British department store, opened Agender, a three-story pop-up shop devoted to gender-neutral clothing. Billed as “a fashion exploration of the masculine, the feminine and the interplay—or the blur—found in between” and featuring more than 40 brands, Agender is an unprecedented investment by a major retailer in the idea of androgyny. But is it simply a seasonal marketing gimmick? Or does it represent a new element of the fashion industry’s future?

Selfridges is not the first big brand to explore gender-neutral clothing. In the last year, Gucci, Prada, Givenchy, and YSL were among the fashion houses that introduced gender-bending collections—often using a mix of male and female models in advertisements. Indeed, androgyny has cycled in and out of high-end fashion for decades. (Consider Helmut Lang’s tailored, minimalist 1990s designs, or André Courrèges’ space-age, geometric designs in the 1960s.) But increasingly, gender-neutral fashion is ditching the catwalk for the sales floor.

One example is American Apparel, which this fall plans to introduce several gender-neutral pieces. Cynthia Erland, American Apparel’s senior vice president of marketing, says that gender-neutral clothes have long been a staple of its offerings, especially hoodies and jackets. “Our customers have always been doing this,” Erland says.

It is those customers—young, trend-conscious but not trend-controlled, and liberated by the Internet—who are demanding a less rigid fashion future.

Fabio Costa is on the front lines of the shift. Costa has spent decades developing his own unique gender-bending style. He recalls receiving threatening phone calls for wearing skirts and dresses in high school. Now, at 31, Costa believes gender-neutral clothing is a potential growth segment for the fashion industry. The two-time Project Runway contestant is building NotEqual, a gender-neutral clothing line, from the ground up in New York City. NotEqual’s designs eschew traditional sizing charts, and each piece is tailored for the customer. Costa makes most of NotEqual’s clothing. He dreams of someday producing the collection in his native Brazil.

The growing presence of transgender people in society and business is also driving the gender-neutral fashion shift. “Fashion is a reflection of what’s going on in society,” Costa says. “Times are different, and therefore, fashion needs to be as well.”

Brooklyn-based design firm TillyandWilliam is also on the front lines of the gender-neutral fashion shift. Jessica Lopidos, the firm’s designer and cofounder, observes that the retail industry’s current acceptance of gender-neutral clothing is different from past incarnations. “In the past,” she says, “it was women wearing the boyfriend sweater. Women wearing a button-up shirt.”

TillyandWilliam’s designs aren’t just about gender; they’re about individuality and sustainability. If the clothes can be easily modified on a regular basis, they are potentially trend-resistant. Clothing should reflect you as an individual, and how you feel changes throughout the day, month, and year. Filled with sashes and snaps and made to fit on different body parts in different ways, TillyandWilliam’s designs are transformable. “Where your hemline should fall today is up to you,” Lopidos says.

Erland, the American Apparel executive, agrees that editability is key for this market. With most items, she says, “it’s more about how our customer styles it” than about any amount of masculinity or femininity inherent in the piece.

To have staying power, gender-neutral fashion must prove its profitability. Until recently, gender-neutral clothes were mostly confined to online retailers and small, independent brick-and-mortar shops. Lopidos remembers her designs being rejected by some traditional retailers. This was partly because, she says, her clothes “didn’t fit into their sections very easily.” Most traditional stores are neatly divided between sections for men’s and women’s clothing. To address this issue at Agender, Selfridges hired interior designer Faye Toogood to rethink the design of the store’s sales floor. As a result, Agender has no gender-specific shopping signs.

If and when gender-neutral gains traction with a mass audience, retailers will have to rethink how the products are explained to consumers. Some boutiques are energetically embracing the challenge, partly because their relative small size allows them to quickly experiment and cater to niche tastes.

All of this drives up the price of gender-neutral fashion—and, for now, keeps it inaccessible to the mass market. A unisex, navy blue square tunic made of tropic wool by NotEqual, for instance, costs $370. An asymmetric jumpsuit costs $350.

Agender is clearly marketed at high-end consumers. Brands such as Commes des Garçons and Rad Hourani created unisex clothes exclusively for the store. Nevertheless, Agender represents an important shift in the fashion industry. “People are actually buying these clothes,” Costa says, adding, “If this does well for Selfridges, soon, we might see a genderless fashion week.”