In November, employees of Rexnord Bearings in Indianapolis, local union representatives and family members of the employees protested Rexnord’s decision to likely move 300 jobs to Mexico. (Photo by Mykal McEldowney/IndyStar)

This week, a 48-year-old man in Chesterton, Ind., posted on Craigslist that he’d like to find love: Looking for a Real Woman. He described himself as a hard worker — “at Steel Mill, so yes I work shifts.” He listed his income at $75,000.

“I am financially stable,” he wrote.

Millennials on Tinder may question his approach, but a new study on the economics of mating suggests the steelworker might know what he’s doing.

Researchers have found the marriage-market value of heterosexual men tends to be tied to their employment status. Data show women are more likely to reject commitment if a suitor can’t help pay the bills. So when jobs disappear, so do potential husbands — and that social shift has particularly rocked areas where manufacturing work has dried up.

Over the past two decades, the United States has lost more than 4.5 million manufacturing jobs — a blow that disproportionately hit men’s employment, since these industries are male-dominated. Though manufacturing makes up less than 10 percent of the economy, factory work for years has offered Americans without college degrees a reliable ticket to the middle class.

After swaths of economic security vanished across the so-called Rust Belt states, President Trump made manufacturing a centerpiece of his 2016 campaign, and voters in Michigan, Ohio, Wisconsin and Pennsylvania — most of whom lacked higher education — helped push him into office. 

A blend of forces drove the job disruption, which has ignited a fierce political debate around the costs of globalization. In 1994, the nation opened seamless trade with China and Mexico, allowing companies to tap cheaper labor beyond the border. Technology, meanwhile, has rapidly advanced, enabling factories to produce more goods with fewer people.

At the same time, marriage rates have dropped. Between 1979 and 2008, the share of married American women ages 25 to 39 fell by at least 10 percentage points across all education levels.

A team of economics professors —  MIT’s David Autor, the University of Zurich’s David Dorn and the University of California’s Gordon Hanson — wanted to understand if these phenomena were related. They dug into government data around birth, marriage, employment and trade from 1990 to 2007, looking for connections between factory shifts and family structure.

“We saw that, in some areas, manufacturing is an economic foundation on which a lot of other social arrangements rest,” Autor said.

After a “trade shock,” or a burst of Chinese imports creating harsher competition for similar American products, he said, jobs dipped in manufacturing-heavy areas. (The authors singled out China because the available data allowed for precise measurements.) The drops, Autor said, were linked to a reduction of what the authors called “marriageable” men.

They found that a trade shock was associated with a 5 percent drop in marriage among young women (18 to 25) and a four percent drop in the birth rate (among women 20 to 39) in manufacturing-reliant areas. The share of babies born outside marriage, however, increased slightly. Autor guesses that’s because marriage is more optional to some women than motherhood, and not every pregnancy is planned.

Trade shocks tended to impact men’s and women’s employment equally, but earnings of men in the lower third of the income distribution fell relative to their female counterparts, the researchers noted. (Since manufacturing jobs are among the highest-paying work someone without higher education can find, there are few financially lateral moves from a shuttered factory.)

When that happened, more young men than in generations past left an area or joined the military. Upticks in crime and early deaths suggested some turned to drugs and alcohol. The trade shocks, Autor said, “made men less attractive.”

Not that women were shallowly seeking out riches. They just had less incentive to form domestic partnerships with someone who lacked the ability to pull their weight.

Which makes the Craiglist steelworker’s search for romance move savvy. In Porter County, Ind., where his post indicates he lives, manufacturing jobs have fallen 9 percent since 2001, from 10,826 to 9,868. Assuming his personal ad is true, he remains gainfully employed — a prerequisite to what Autor and his colleagues consider “marriageable.”