Marcus Genzlinger had no idea how bad it was until his girlfriend forced him to face the truth.

“She showed me a picture from a wedding where I had see-through hair,” he said.

The marketing consultant had been obsessed with his thinning hair for years. “I always worked too hard to style it right and tried to hide it,” he said.

After his girlfriend’s “intervention,” Genzlinger, now 39, shaved his head. He has been a chrome dome ever since, something that “makes me feel more confident and comfortable,” he said. “And I think it makes me look younger.”

Gerzlinger is part of a cutting-edge trend that started about a half-dozen years ago and shows no signs of receding.

A recent study at the University of Pennsylvania’s Wharton School showed that men with very closely cropped hair and shorn heads are regarded as more virile and commanding than their more hirsute peers. It also found that men with thinning hair were viewed as weaker and less attractive.

Not good news for the 35 million American men with male-pattern baldness. But as more men have forgone a cranial cover-up, the look has become more socially acceptable, especially among younger men and the women who like them.

“You’re seeing the next generations below boomers joining the ranks. It makes a statement,” said Teresa Daly, co-founder of the Minneapolis executive-placement company Navigate Forward.

“Women for years have been screaming about how they prefer a bald guy to someone who’s trying to look like he’s got hair that he doesn’t have,” Daly said. “It’s now not only an accepted but admired look.”

Note to Donald Trump: The comb-over is dead.

Throughout history, the few bald men in power tended to be stately (Mohandas Gandhi, Winston Churchill, Middle Ages emperor Charles the Bald). More recently, manly men in the worlds of sports (Michael Jordan, Kevin Garnett) and action movies (Bruce Willis, Jason Statham) have gone the buzz route.

As these icons have turned an obstacle into an attribute, many men are emulating the look, especially when nature calls.

“In my 30s, it was an even race to see if I would go bald first or gray first,” said Jon Austin, president of the Minneapolis consulting firm J. Austin & Associates. “Then as my hair got thinner on top, it was starting to look weirder and weirder on the side. I knew it was time when somebody in my family said, ‘You look sort of like a mad scientist.’ ”

So about five years ago, Austin went for the close-cropped look. Immediately, he felt better about himself, he said. He also discovered that there were professional benefits to being seen as “that archetype of the bullet-headed tough guy.”

“I do a lot of crisis and issue management,” Austin, 53, said, “and my intuitive belief is clients want to see somebody who’s been around the block. Nobody would look at me and say this is my first rodeo.”

For Ivan Nunez, creative director of user experience at the Minneapolis ad agency Olson, taking the going-going-gone route was just part of an appearance overhaul.

After determining “it was time to just let it go” about five years ago, Nunez went about creating a whole new “comfort zone.”

“It has changed the way I dress,” he said, “maybe a little more casual, not so much button-down shirts, more sweaters. I think I look younger, and I’m definitely more relaxed.”

For younger men, though, a bald pate may be more of a styling issue, said Bob MacDonald, a manager for executive recruiter Russell Reynolds Associate.

“A lot of this thing is generational,” said MacDonald, who is based in Minneapolis. “People in their 20s and early 30s are choosing it as a look. It’s just a much cleaner look.”

Nunez, Genzlinger and others complement their shiny pates with facial hair, including the endlessly popular goatee. But it turns out that a super-short cut isn’t limited to a buzz cut from a septuagenarian named Shorty.

“I love doing short haircuts,” said Tim Foster, a stylist at Minneapolis’ Studio 52. “It’s not just like somebody zips over their head all over the place. It’s a really, really precise cut, but a short one.

“You can go with a lot more modern edge, get it cut more geometrically, get weight lines that are noticeable but subtle. A lot of times I’ll do an unnoticeable faux-hawky thing so they can do something with it on the weekends.”

Foster said a large percentage of his male clients have gone with the short cuts, although some might waver. “Lots of people get sick of it and then try something else,” he said, “but they always, always come back to short hair.”

Except, perhaps, for the men in one industry.

Minneapolis station WCCO-TV’s peripatetic reporter Jason DeRusha started balding in his 20s and recently opted for a hair transplant.

“I’ve always been a little self-conscious,” DeRusha, 37, said. “It’s a funny thing. WCCO would never, ever say, ‘Look, you don’t have enough hair on your head.’ But the reality is, if you look at every person who gets promoted into an anchor or a correspondent’s job, you never ever see anyone with thinning hair.

“Maybe the real world is moving faster than the television world.”