It is often the case that, as summer rolls around and temperatures rise, so do hemlines. As men have embraced shorter shorts over the past few years, some have also started to wear shorter shirts — specifically, crop tops.

Though men have been known to wear stomach-baring garments when they exercise or go to the beach, lately crop tops can be seen on guys at stores and bars. More modest styles hit right at a waistline, but many are cropped short enough to expose a navel. Some wearers are making theirs by taking scissors to old T-shirts; others buy them off the rack, often from stores’ women’s sections.

David Mendoza, 29, an operations manager in New York, owns crop tops of varying lengths. Deciding which to wear, he said, often comes down to the occasion.

“If I’m wearing one just to go out casually, the crop top will be mid- to long length,” Mr. Mendoza said. If he is going out with friends, or if he wants a crop top to be the centerpiece of an outfit, he will choose one that shows a lot more skin.

At first, Mr. Mendoza would cut shirts himself. But as he started to wear more crop tops, he discovered that stores including H&M and Rainbow sold women’s styles with his preferred fit. Rainbow, he said, has “sexier, more open crop tops that are cut even shorter.”

Mr. Mendoza started wearing crop tops about two years ago, he said, after noticing that some male fitness influencers he followed on Instagram wore them to exercise. “I was like, wow, they look really good, and it looks so normal,” he said.

But it was only recently, when Mr. Mendoza accidentally packed a crop top for a workout, that he wore one at a gym. “I was pretty self-conscious about it,” he said.

To boost his confidence, Mr. Mendoza posted a picture on Instagram that showed him wearing the shirt with the caption: “Let’s normalize crop tops in the gym.” Afterward, he said, “I started getting friends posting themselves in a crop top at the gym and tagging me.”

Ethan Garland, 25, a photographer and videographer in Chicago, said he has also gotten enthusiastic responses to his crop tops. Since he started wearing the shirts last year, he said, they have become “sort of like a uniform” for him.

Mr. Garland said he was drawn to crop tops because they make his legs look longer. As a man, he added, “if you’re willing to do something slightly past the norm, something past the bare minimum, people usually appreciate it and take notice of it.”

Some men say the attention crop tops attract can be unwanted. Joseph Damian, 22, a content creator in Fresno, Calif., said he started adding the shirts to his wardrobe about three years ago and that he has been wearing them in public for about a year and a half. “I’ve had people like look at me weird because I’m wearing one,” he said.

Negative attention has not deterred him, though, and he has posted videos on TikTok that show other men how to make and style their own.

“I feel like the way to actually rock a crop top is to just be confident,” Mr. Damian said.

Ben Barry, the dean of fashion and an associate professor of equity and inclusion at Parsons School of Design in New York, said crop tops have emerged as a men’s wear trend before.

In the 1980s, he noted, they were briefly “the epitome of American straight masculinity in football” after many players started to rip their shirts to expose their stomachs. He added that Johnny Depp wore a crop top as Glen Lantz in the 1984 film “A Nightmare on Elm Street,” and Will Smith later wore a crop top in TV show “The Fresh Prince of Bel Air.”

Codey James, 27, who works in advertising in New York, said he grew up watching movies and TV shows from the ’80s and ’90s. He started wearing crop tops about a year ago, he said, and was influenced in part by the styles he saw on-screen when he was younger.

Mr. James said that about 70 percent of the shirts he owns are cropped. Most, he added, hit below his navel, though a few are short enough to show it.

“My girlfriend always makes fun of me because sometimes she just wants a shirt to wear to bed, but they’re all crop tops,” he said.

Professor Barry said that men wearing crop tops comes at a time of “shifting dynamics of gender” and an “openness in masculine fashion to truly embrace a variety of aesthetics.” He added that the trend is relatively affordable for most men, requiring only a T-shirt and a pair of scissors.

To some men, Professor Barry said, crop tops can be more than just a fashion statement. He said he has seen crop tops embraced by men with larger bodies “as a way to really kind of affirm their bodies and challenge stigmas against their bodies in public spaces.”

Xander Torres, 30, a college student and waiter in Vancouver, Wash., said he started making his own crop tops last summer by cutting the bottoms off some of his favorite vintage T-shirts. “It seemed like everybody was cropping all of their stuff, and I kind of fell into that trend,” he said.

But as he tried to crop more of his shirts, Mr. Torres said he “went a little overboard,” cutting some a little too short and others on a diagonal.

“My new rule is that if it’s a single-stitch vintage T-shirt, maybe just tuck it in,” he said.