The following is based on Marriage Markets: How Inequality Is Remaking the American Family, out in May 2014 from Oxford University Press.

Lily had grown up in a rural town, more than an hour from Kansas City, Mo. She was four months pregnant and not feeling well, and she was in tears. She was also not married, but that’s not what was upsetting her. The car that she needed to get to her two jobs in the city had broken down, and she had no other way to get to work. We asked whether her boyfriend, Carl, could help her. Lily frowned. She had recently broken up with Carl, she explained, because “I can support myself. I always have. I can support myself and our kid. I just can’t support myself, the kid, and him.”

Was Lily just being stubborn? Unrealistic about what it actually takes to raise a baby? Soon after the baby was born we interviewed Lily again. A lawyer had helped Lily get a refund for the car. Her parents, devout Christians who supported both her decision to have the child and her decision not to marry Carl, were helping with child care. Carl was still not part of the picture, and Lily had no regrets. In her mind, Carl would get in the way of her ability to raise her child.

A generation ago her decision would have seemed narrow, misguided, and difficult to understand. But now we have to conclude that it makes a lot of sense. Although it defies logic, socioeconomic, cultural, and economic changes have brought white working-class women like Lily to the point where going it alone can be the wiser choice. And the final irony: The same changes that have made marriages more equitable and successful among elite couples have made it less likely that marriage will look attractive to Lily.

When Lily looks around at the available men, they don’t offer what she is looking for. Lily, just like better-off men and women, believes that marriage means an unqualified commitment to the other spouse. When you marry someone, you support him in hard times. You stick with him when he disappoints you. You visit him if he ends up in jail. And you encourage him to become an important part of your children’s lives. It’s just that Lily doesn’t believe that Carl is worth that commitment. Nor does she believe that she will meet someone who will meet her standards anytime soon, and the statistics back her up.

The economy has changed. A higher percentage of men today than 50 years ago have trouble finding steady employment, securing raises and promotions, or remaining sober and productive. Blue-collar men like Carl have lost ground while more highly educated men have gained. The unemployment rate for all men ages 20–24 is almost 13 percent, and those with only a high school education are more than twice as likely to be unemployed as those with a college degree. Moreover, many of the jobs that are available have become less reliable than they were for Carl’s dad. They don’t pay as well, last as long, or offer promotions or training. Carl has quit more than one job because he got fed up with his boss. More recently, he was laid off because construction work dried up during a particularly cold spell during the winter. After the layoff, he hung around with his friends, drinking and playing video games. Lily finally had enough when she found out that Carl had run up several hundred dollars in expenses on her credit card. Lily knows she will never be able to depend on him and, particularly now that she has a child, she doesn’t believe she can afford the risk. It is not surprising that marriage rates for men in the bottom quartile of earnings have fallen dramatically, from 86 percent in 1970 to 50 percent today.

At the same time that men like Carl have lost ground, women like Lily have gained. While almost no one outside the top executive ranks has gained much since the financial crisis, women in the middle of the American economy saw greater increases than the comparable men in both pay and job stability through the ’90s. That doesn’t mean that ideas about who should be the breadwinner have changed much, though. Both men and women generally agree that a man who can’t hold a steady job shouldn’t marry. Indeed, “the less education and income people have, the more likely they are to say that to be a good marriage prospect, a person must be able to support a family financially.”

The women ready for marriage in this group have grown larger than the group of marriageable men who would be good partners. These men—the ones with better jobs and more stable lives—have become more reluctant, in turn, to settle for only one woman. Their marital prospects have improved, and they could marry a reliable partner. Yet, with a choice of committing to a woman who outearns them or keeping their independence, the men seem to prefer their freedom. Lily did go out for a while with a more promising high school classmate. But then she discovered text messages with another woman on his phone. The experience left her jaded. She has very few friends, married or unmarried, in strong relationships, and she did not see much point in waiting for a Prince Charming she did not expect to find. Indeed, while less than 20 percent of the most highly educated Americans believe that marriage has not worked out for most of the people they know, more than half of those who are least educated believe that marriage has not worked out.

One final factor pushing Lily away from marriage is, ironically, more progressive ideas about family, particularly in divorce courts. The biggest legal change is custody. If a couple marries, a court will insist on a custody order and it will expect that both spouses continue their relationship with the child. Indeed, some states presume that the child should spend approximately equal amounts of time with both parents. These changes make marriage a better deal for elite men. They do not need to make a long-term commitment to support a dependent partner as lengthy spousal support has largely disappeared, but they enjoy protection of the relationship they establish with their children. Women initiate two-thirds of all divorces, and some law professors have argued that shared custody is one of the factors that has lowered divorce rates.

If Carl and Lily had married, Carl would have automatically been named the father, and, if they divorced, the courts would insist on an order giving Carl a considerable portion of the child’s time. Carl, however, was not at the hospital with Lily and his paternity has never been established. Lily has let Carl see the child, but he hasn’t pressed for more involvement and Lily is happy to keep it that way. If Carl wants more contact, he would have to take a series of legal steps, including filing a court case, paying the several hundred dollars it would cost for paternity testing, obtaining a court order, and enforcing it if Lily doesn’t cooperate voluntarily. If Carl were that organized and determined, though, he didn’t show it during their relationship. And, in fact, University of Wisconsin researchers find that the likelihood that a father has shared custody of his children after a breakup correlates strongly with marriage (husbands are much more likely to have a shared custody order than unmarried fathers) and with the father’s income within each group (husbands, for example, with more money are more likely to have such orders than poorer husbands). In divorce court, Carl’s lack of financial or other contributions would typically make little difference in either the property division or a custody award. By not marrying, Lily can leave the relationship on her own terms—with her savings intact and no responsibility for Carl’s debts.

Does society have an interest in helping couples like Lily and Carl stay together? Probably, but not in the way many policymakers have proposed. Those who would promote marriage seek to do so largely by taking away Lily’s independence. New York Times columnist Ross Douthat, for example, suggests that more restrictive abortion policies could increase the marriage rate. And many who seek to promote marriage, like the Catholic Church, link the availability of contraception to the sexual freedom they see as responsible for the decline in marriage. Others, like Charles Murray, would cut programs such as Medicaid, food stamps, early childhood education and child care, mandatory family leave, and other policies that make it easier for women like Lily to raise a child on their own.

In our view what would make the most difference to this unfair marriage market are policies that would increase the number and quality of jobs available to working class men, retraining and unemployment benefits that fill in the gaps between jobs, and ongoing support for women’s autonomy. Since the ’80s, the gender gap in wages has increased at the top but shrunk in the middle. As a result, Lily finds that she can say no to marriage and raise a child on her own. Modern family law protects the interests of elite men who make an investment in their children. It does not recognize the burdens of women like Lily who are often both the more reliable breadwinner and the primary caretaker in their families—and of the men who are shut out of their families. Let’s not make raising a child become yet another marker of class.