Decades of research show that on average, children who grow up with parents who are not married and living together have worse achievement and behavioral and well-being outcomes than children of two-parent homes. Despite this evidence, rates of nonmarital childbearing have risen dramatically in the U.S., especially among the noncollege-educated. What then can be done to help the increasing number of children growing up outside of married, two-parent households to flourish?

While we need many good ideas on the table, policymakers should look very closely at one demographic phenomenon: the positive outcomes of low-income children who live with their grandmothers. And there are lots of them. America has seen a marked rise in these multigenerational households, driven by the realities of single parenting, as well as myriad economic, housing and other headwinds.

This does not mean that society should abandon the idea of marriage. Marriage can go a long way toward increasing children’s economic resources. It can also provide the setting for the time, attention, affection, and family culture and traditions that help children thrive.

But we should abandon the idea that a married household with two “original” parents is the only type of household that can provide these ingredients for healthy child development. Single parents living with their child and a grandparent in a multigenerational household can provide these crucial ingredients while also helping stabilize low-income families economically.

My colleague Thomas DeLeire and I have found in our research that low-income Black teenagers living with their unmarried mother and a grandparent have superior achievement and behavior compared to similar low-income Black teenagers living with their married parents (and not with a grandparent). Scholars including Kathryn Edin and William Julius Wilson have long posited that adverse economic forces affecting low-income couples — i.e., job loss, unemployment, income instability — can cause relationship strife and disrupt parent-child engagement. In these contexts, grandparents may be better able to support the child’s development than resident biological fathers who are being buffeted by these economic headwinds.

In a related paper, along with my colleagues Rebecca Ryan and Elise Chor, I studied time investments in children across different living arrangements. Time investments do not fully capture the experience of parenting, but they are widely viewed as an important vehicle through which children’s skills develop in their home environment. Most studies of this type look at how parents and caregivers spend their time on children. We, instead, looked at how much time children receive from their caregivers within their home. We found that children living with their single mother and one of their grandparents receive no less total time investment than do children living with their married parents. Indeed, comparing children in single-parent multigenerational households versus those in married-parent households (without a grandparent), children receive the same share of time from their grandmothers as from their resident biological fathers.

Survey respondents in the U.S. report that multigenerational living arrangements are socially acceptable. (Indeed, this arrangement is common in other countries.) Multigenerational householders describe their living arrangements as a long-term commitment. On average, they say it is a positive and rewarding experience. It reduces poverty and is an important setting for providing and receiving care in both directions across the generations.

Policymakers have not caught up to these realities. About 20 years ago, President George W. Bush’s administration gave $1.5 billion to the states to encourage low-income unmarried couples to enroll in marriage education programs to help them form “healthy marriages.” These programs had little effect on marriage rates.

There’s another path forward: We should aim to improve the outcomes of children who are already being raised outside marriage. Strengthening the economic safety net for single mothers is an important starting point. The government could also spend money on child care or schooling to help boost outcomes for children in different household structures. Whether the U.S. government has the appetite for any of these subsidies, however, is far from clear.

Getting creative about government supports for new types of living arrangements should be high on the policy agenda. Unfortunately, the U.S. lags its peers in this regard. The United Kingdom has a National Insurance (state pension) credit for grandparents caring for grandchildren younger than 12. Portugal has a grandchild care allowance that allows working grandparents living with a very young parent and the baby to take a period of leave of up to 30 consecutive days. These policies are sensible and feasible.

The economic forces gathering speed and shaping family behavior in the U.S. demand fresh policy solutions to support children’s development. Multigenerational parenting arrangements work well in other countries, and they are proving viable here too. We must acknowledge this and support them.

The old saying “good things come in threes” — especially when answering the question of how many generations make a happy, nurturing, future-focused household — should be part of a new guide to effective family policy.

Ariel Kalil is the Daniel Levin professor at the University of Chicago Harris School of Public Policy.