For every dollar a man makes in the U.S., women 30 and younger currently earn about 93 cents. According to a Pew Research Center analysis of Census Bureau data released last week, young women earn the same as, or more than, their male counterparts in just 22 U.S. metropolitan areas—that’s less than 0.1% of major cities.

Also not surprising, though disheartening: Heterosexual marriages where the wife earns more than her husband are more likely to be marred with communication issues, resentment, and infidelity, and ultimately result in divorce.

While a family being helmed by a female breadwinner is no longer the anomaly it once was (in 2018, 53% of families relied on earnings from both the husband and the wife, according to the Bureau of Labor Statistics) the idea of a woman outearning her husband remains unusual—and sometimes contentious. 

Joanna Syrda, an assistant economics professor at the University of Bath School of Management in England, recently studied over 6,000 heterosexual North American married households in which wives outearn husbands. 

In response to “deviating from the gender identity norm,” Syrda’s research found these couples often fall into more traditional roles through housework: The women do more and the men do less, which she calls “gender deviance neutralization.”

That “gender deviance” may also show up in smaller, more telling ways. A 2018 Census report compared what respondents told Census surveyors about their earnings to their IRS tax filings. In heterosexual marriages with female breadwinners, women reported an average of 1.5 percentage points less than they actually earned, while the husbands inflated their earnings by an average of 2.9%. The researchers called the phenomenon “manning up and womaning down.”

This data all stems from the assumption that a powerful woman gets married at all; a Census data analysis by researchers at the University of Chicago and the National University of Singapore in 2015 found that fewer people get married in the places where women commonly outearn men. 

Breaking the taboo

Farnoosh Torabi, a finance journalist and editor at large of CNET Money, wrote the book on women outearning men. And she lives it: She outearned her husband when they got married.

“I’ve been a financial journalist my whole career, but it was a financial topic I suddenly felt I couldn’t talk about,” she says. “I felt it was making people awkward when I even tried to bring it up at a dinner party. My mother and I battled over it especially; she did not trust that this was a sustainable economic arrangement for a man and wife.”

“No one talks about it because it’s uncomfortable,” Kara Alaimo, an associate professor in the Lawrence Herbert School of Communication at Hofstra University, tells Fortune. “The data tells us that women, on some level, know [outearning their husbands] is going to be a problem for them in their relationships.” 

In her research, Torabi has found the taboo is far from an anomaly. Since the 1960s, the percentage of households with women making more than men has quadrupled. 

“When you’re willing to accept or embrace this dynamic, it can be a beautiful thing,” Torabi says. “It doesn’t have to be this challenge, or a difficult thing to overcome.”

In researching for her book When She Makes More: 10 Rules for Breadwinning Women, Torabi came to believe the income differential isn’t necessarily the cause of marital strife, but the correlation can’t be ignored.

“But it doesn’t have to be that way,” Alaimo says. “Destigmatizing the idea of a man having a more successful partner is key. We do that by rethinking our cultural approach: What we tell boys and girls as they age, and how we talk about success and values.”

“This isn’t a women’s issue; it’s a societal problem everyone needs to work on,” Torabi says. “We need all hands on deck.”

Alaimo points to Douglas Emhoff, the first Second Husband in the U.S.—who met Kamala Harris when she was already attorney general—as a prime example. “He has, from all outward accounts, celebrated her career,” she says. “The more men see other men like that in the public eye, the more it gives them permission to do the same.” 

When it works, it works

Some couples are ahead of the curve.

Elena Perez, a 49-year-old mother of two in Sacramento, has outearned her husband for the entirety of their marriage. Perez, who works in communication for a labor union, acknowledges that her setup is unusual but ultimately the best choice for her family.

Perez’s husband has mostly worked in service jobs, such as IT support, delivery work, and serving as a crossing guard at their kids’ school. When COVID hit, the family decided the infection risk of most of those jobs was too high, and it would make more sense for him to take on the childcare duties. He’s been a stay-at-home dad ever since. 

“We just recently had a conversation about how much better and more smoothly our house runs with him taking on the traditionally female role,” Perez tells Fortune.

Before Perez’s husband quit working, the couple considered her income as their primary income source for bills and expenses, while his income was “bonus money.”

“The way we put it is: My salary is what enabled us to buy our home; his money was the down payment,” Perez said. “Maybe our setup wouldn’t work for everyone, but it works for us.”

Perez acknowledges that hot-button issues like sex, politics, chores, and money are what can often lead couples into dangerous territory. But she says she and her husband have never argued or experienced tension over their financial arrangement. 

“I’ve always made significantly more; it’s just about communication,” she says. “We ask, how do we best serve the needs of our family? Instead of, how do we best serve what the external world thinks we ought to do?”