If you imagine a single woman having a baby around 1980, what do you think her life has been like since? By the time that child became an adult, was the mother any better off than she had been when the child was born? In an article published late last month in Demography, Matthew Painter, Adrianne Frech, and Kristi Williams challenge what they say “is often an oversimplified picture of single mothers as more impoverished and less educated than women with a marital first birth.” The part that is oversimplified is assuming that single mothers necessarily stay poor: Painter and his co-authors show that women who have nonmarital first births gain assets (not debt) over time.

Their study is the first to investigate long-term changes in wealth among women whose first births were nonmarital. Other measures of socioeconomic status like income, education, and employment status show clear disadvantages, contributing to a picture of nonmarital childbearing as the glue that keeps some women stuck in poverty. But the long-run evidence showed that even women who stayed single accumulated wealth over time.

Staying single was, nonetheless, associated with slow wealth accumulation. Which mothers gained wealth faster? Entering a marital union helped, while entering a cohabiting union didn’t; staying married helped, while simply getting married didn’t; and marrying the child’s father and staying married to him helped most of all. The women stably married to their child’s father gained about $3000 per year, much more than the $612 per year average of those who remained single. Lest this sound like the authors are clearly behind marriage promotion programs, let’s be sure that we consider all that they say.

First, they found that only 24 percent of the women who started their reproductive careers with a nonmarital birth later married their child’s biological father and were still married to him by the time they turned 40 (around the year 2000). Another 13 percent got married to the child’s biological father, but later divorced: among those women, the average age at marriage was 18.51 and the average years spent married was less than three.

Second, not all women face equal chances of marrying after childbirth. If 24 percent still married to the biological father at age 40 sounds low, consider that it comes from a nationally representative sample of women having a nonmarital birth. Among low-income women having a nonmarital birth, 16 percent were married to the biological father just five years later. That makes 24 percent about 20 years later sound rather good.

In fact, one of the more impressive pieces of these researchers’ analysis was that they showed that their overall results were biased by the fact that non-Latina black women were particularly unlikely to marry after childbirth. Their initial analysis had indicated that any women who had entered marital unions had faster wealth accumulation than those that remained single, but after accounting for selection into marriage, marriages ending in divorce no longer helped. That means that marriages ending in divorce were associated with faster wealth accumulation only because better-off women married, not because marriages that dissolved actually helped. After their correction, divorced women ended up with the same assets as continuously single women. Only enduring marriages contributed to accumulated wealth (and that was not explained by better-off women marrying). Nonetheless, the authors caution that if stable marriage were promoted among less advantaged groups, the wealth premiums associated with it would likely diminish.

Their work echoes previous findings that marital disruption reduces financial stability. It also contributes to the picture of how large the challenges for marriage promotion are: 37 percent of relatively advantaged women married the biological father of their child (they had higher baseline wealth), and over a third of those became divorced from him. The less advantaged marry at lower rates, and they are more likely to cohabit. Theoretically, cohabitation could contribute to wealth accumulation because housing costs are shared and childcare costs can also be lower if both partners contribute time. But it didn’t. Both mothers who cohabited with their child’s biological father and those who cohabited with other men did no better than mothers who remained unpartnered.

The bottom line is that stable marriage promotes women’s wealth accumulation. There is an additional “premium” if that stable marriage is with the child’s biological father, but wealth accumulates faster among women stably married to other men as well (though the chance that stepfather marriages will be stable is lower). Painter and his colleagues remind us repeatedly that stable marriage is not an easily accessible commodity. It is harder to come by for women with a premarital birth; it is harder to achieve with non-biological fathers; and it much less attainable for non-Latina blacks: “not all women have equal access to the wealth benefits of stable marriages.” The authors also present their results for divorced women as a challenge to the idea that marriage will necessarily improve women’s well-being following a nonmarital birth.

So there are a number of reasons why these findings do not translate into a prediction that encouraging marriage among single mothers will confer upon them higher wealth accumulation rates. But the work nonetheless supports the notion that stable marriage is good for women, not just their children. We already knew that women experiencing fewer union transitions are healthier, and now we know that they are also wealthier—even if they start out with the deck stacked against them by a nonmarital birth. A nonmarital birth can provide a ticket to the marriage-go-round (or, more likely, the cohabitation-go-round), but it does not have to.