At a wedding reception I attended recently, the mother of the bride, tired but happy, rose to offer a toast. I was struck by one point she went out of her way to emphasize — namely, how overjoyed she was that the guests who had flown in from out of town included not just her daughter’s married siblings and their spouses but also the parents of those spouses. Some of those in‑laws, she noted, were now attending their third or fourth wedding together. Gathered in the ballroom, in other words, were more than just two nuclear families that had come together to celebrate a marriage. Instead, there was an extended web of in-laws and the in-laws of those in-laws — multiple generations from multiple families, rejoicing as yet another branch was grafted onto a family tree that continues to spread outward and sink its roots deeper.

Under the wedding canopy earlier that day, the bride and groom had united in an ancient ritual to begin a new family. But at the same moment, the newlyweds were also joining a sprawling constellation of people — many of them former strangers who, wedding by wedding, visit by visit, were slowly becoming, to use a resonant old American word, kinfolk.

A wedding doesn’t just unite a couple; it fuses two networks of relations. And that fusion is one of the underappreciated strengths of marriage — especially when there are children in the picture.

Pundits, politicos, and policymakers talk about the benefits of married, two-parent families in predictable terms: greater stability, higher income, better supervision, more consistent expectations. Those advantages are significant, and social science has documented them amply. But there is another advantage, one that isn’t articulated in public debates nearly as often: Marriage doubles a child’s network of relatives.

Researchers have long noted that a strong predictor of children’s well-being, in addition to who raises them, is how many people they are connected to. A dense network of kin works like a shock absorber, softening blows and making life’s rough bumps easier to get through. Of course, there are no guarantees. But as a rule, extended family ties tend to provide a buffer against adversity. Children embedded in robust kin networks are more likely to complete high school, avoid early pregnancy, and develop the emotional steadiness that helps them succeed as adults. When those connections are thick, children are generally safer; when thin or nonexistent, children are at greater risk.

This is a practical matter much more than an ideological one. Families help one another in ways great and small — a grandparent steps in during a crisis, a brother-in-law flags a job opening, a cousin agrees to invest in a fledgling business, an aunt gives her old car to a teenager heading to college. These acts of support may not show up on census forms or in economic statistics, but they can make all the difference for a young person’s prospects.

Because kids with married parents typically have access to a broader base of support than those raised by a single parent, they are more likely to thrive. In virtually every known society, the anthropologist David Murray observed in 1994, marriage provides “bridges of social connectedness.” Across human cultures and eras, marriage is unequaled in its ability to turn unrelated people — even formerly wary ones — into members of the same tribe. “By uniting with outsiders,” Murray wrote, “marriage helps families multiply their economic capital — and, perhaps even more important, their social capital.”

By contrast, kids growing up without married parents — which in contemporary society most often means being raised by a single mother — lose much more than the presence of a father. They lose the father’s family network as an active force in their lives, with all the gifts of love and memory, protection and sustenance, the network might have provided.

It’s an ancient insight. One of the most beautiful stories in the Bible — the Book of Ruth — is, at heart, a tale of family networks knitting themselves together across generations. Ruth, a foreign widow, binds herself to her mother-in-law Naomi and adopts Naomi’s kin as her own (“Your people shall be my people”). That act of loyalty pulls her into a new family whose protection and stability she desperately needs. When Boaz, a distant kinsman, agrees to marry Ruth, he gives the young widow a new lease on life and ensures that Naomi will not be left destitute. The narrative is lovely, but it is also a study in how extended family provides strength, continuity, and a future.

None of this implies inevitability. Children raised by married parents can still struggle, and children raised by single parents can and do flourish. The world contains many successful adults who grew up without fathers — none more emblematic, perhaps, than Barack Obama.

Standing in a Chicago pulpit on Father’s Day in 2008, Obama, then a senator, spoke from the heart about the importance of family ties, especially to kids who are denied them.

“Of all the rocks upon which we build our lives, we are reminded today that family is the most important,” Obama said. But because fathers are “missing from too many lives and too many homes … the foundations of our families are weaker because of it.”

He cited sobering statistics. “Children who grow up without a father are five times more likely to live in poverty and commit crime, nine times more likely to drop out of schools, and 20 times more likely to end up in prison,” he told his audience.

As president a year later, Obama spoke again about growing up without a father in his life and how keenly he felt that absence. “That’s something that leaves a hole in a child’s heart.”

But a missing parent also leaves a hole in a child’s kinship network. The mother of the bride at that wedding earlier this month may not have invoked the findings of social scientists, but she understood them instinctively: Good marriages do more than unite two newlyweds. They also graft households to households, widening the circle of people who show up for one another, who care, who take responsibility. It was that to which she raised a toast — the quiet miracle of two families, once strangers, now choosing to stand behind the same children and share in the same future. Of all the gifts the new couple received that day, that widening circle of kin may prove the most precious of all.