NEW YORK — It’s been a bit hard to tell the difference between men’s and women’s runway presentations at the fall 2013 fashion shows.

Nautica’s Black Sail collection had its male models in banana-yellow skinny pants rolled at the ankles. Coats with oversize fur collars featured a slight A-line flare.

Designer Patrik Ervell’s presentation last Sunday included an iridescent, emerald-green cape with a wraparound, cowl-neck collar.

Even Michael Kors — whose manly clothes are typically classic American with a dose of Old World sophistication — dressed a model Wednesday in a fuzzy, short-sleeve sweater and skinny slacks, while another wore a bright-orange, belted trench.

American menswear has officially dipped its pantleg into the expanding androgynous-loving pool of the fashion industry. That means not only will women wrap themselves in their boyfriends’ sweaters, but men may soon be donning "girlfriend" jeans as well — and their sexuality won’t be questioned. Or at least, they will be confident enough not to care.

"It’s all very urban nomad," said Tom Julian, trend-watcher and author of Nordstrom’s Guide to Men’s Everyday Dressing, while he took a break at New York Fashion Week. The guy who wears these clothes is "one-part artist, one-part rebel, and he’s also very simplistic; he loves his technology," Julian said.

Womenswear has been borrowing masculine details since the 1920s when Coco Chanel essentially created the women’s suit. The look was initially considered taboo, but using men’s fabrics and tailoring in women’s clothes today (see Michelle Obama’s Thom Browne coat at the inauguration) is as accepted as wearing red nail polish.

Yet since men took off their wigs, long stockings, and knee breeches around the start of the Industrial Revolution, they’ve been languishing for 200 years or so wearing shirts and trousers in navy, black, and gray shades. Now it seems that younger, heterosexual men are actually following fashion as closely as women. And with more clothing options, they have to replenish their closets to stay in style.

Sales reflect that. As of November, total U.S. menswear sales were up 4.2 percent, to $55.6 billion, from $53.4 billion the year before, according to the market research firm NPD Group.

"The industry is understanding now there is a market for men," said Michael D. Oxman, image consultant for Philadelphia-based Henry A. Davidsen, a custom-suit retailer. He has seen his fitted-suit sales go up in the last year.

Men "are starting to consume (fashion) at a similar rate as women. That’s just the market at work," Oxman said.

Besides the fact that most models now look like adolescent boys, the androgynous movement is reflective of both European runways — especially collections by Rick Owens, an American designer in Paris who is credited with creating a multilayered men’s look featuring skinny cargo pants, infinity scarves, and long, cozy cardigans — and celebrity culture. Check out the red carpet or fashion websites to see Chanel accessories (not made for women) worn by male rappers.

And at the Grammys last week, many men appeared enamored with dandy details: Drake wore a fitted tux; John Mayer showed up in a shrunken purple, velvet blazer; and crooner Ne-Yo stunned in a metallic jacket and silky cargo pants. (Ne-Yo later performed at Fashion Week at a Prabal Gurung for Target presentation wearing a pink blazer and sequin scarf.)

The NFL-loving man, on the other hand, might be slower to embrace these trends, said Daniel Abraham, creative director of Art in the Age, a men’s store in Philadelphia.

Back in New York, the Lincoln Center runways weren’t the only places where menswear and womenswear seemed indistinguishable. At Chelsea’s Milk Studios, where many emerging designers show off-site, Carlos Campos presented male models wearing rosy lip color and tight, floral-printed slacks. Lucio Castro experimented with colorblocking — typically the domain of womenswear — and Rochambeau layered turtlenecks under hooded cloaks with three-quarter-length sleeves.

"These days, men can wear a woman’s navy cashmere sweater and it’s OK," said Quentin Washington, a Philadelphia-based blogger. "I saw collections like Robert Gellar, where he showed quilted, knee-length shorts over tights. I saw collections with belted cable sweaters. All of these pieces are women’s clothing, but they work in menswear now, thanks to layering."

For the second season, Details magazine hosted a handful of runway presentations and an accessories show geared specifically to men. Although the music was 1990s hip hop and showgoers were handed bottles of Yuengling and Heineken, the vibe was not gender-specific.

Not only were attendees clad in ponchos and metallic high-top sneakers, but also the nine accessories brands ranged from camouflage and leather duffel bags to thin friendship-like bracelets, some with dangling charms.

"When I walked in and saw those bracelets, I thought to myself, ‘Is this really a men’s show?’ I mean, I really want them," said Maria Ambrose, 25, who walked through the show holding the hand of her boyfriend, Matt Fennel.

What did Fennel think?

"I’m not a big fan because I tend to be more rugged," he said (while wearing fitted burgundy corduroys). "But I am paying more attention to fashion. I mean, five or six years ago, I wouldn’t have these on, so, yeah, it is an evolution."

Slowly but surely, men aren’t letting fashion rules define their clothing choices, let alone their sexuality, said Colin Stark, development director of Details magazine.

"I think the ‘90s were all about the masculine form," said Stark, on his feet a pair of blue, brown, and red Gucci tie-up shoes. "Now men have more options. They are more comfortable and they are pushing the envelope, challenging the norm."