Amid all the emotion over same-sex marriage, the limited-government argument for marriage as uniting a man and a woman keeps getting short shrift. It fell to me to make that case during a discussion of marriage law and the Supreme Court with the worthy S.E. Cupp on a recent installment of “Real News from The Blaze,” and I’d like to flesh out those thoughts here.

For starters, virtually every political community has regulated male-female sexual relationships. This is not because government cares about romance as such. Government recognizes male-female sexual relationships because these alone produce new human beings.

For highly dependent infants, there is no path to physical, moral, and cultural maturity—no path to personal responsibility—without a long, delicate process of ongoing care and supervision to which mothers and fathers bring unique gifts. Unless children mature, they never will become healthy, upright, productive members of society.

Marriage exists to make men and women responsible to each other and to any children that they might have.

Marriage is thus a personal relationship that serves a public purpose in a political community. As the late sociologist James Q. Wilson wrote, “Marriage is a socially arranged solution for the problem of getting people to stay together and care for children that the mere desire for children, and the sex that makes children possible, does not solve.”

The late atheistic philosopher Bertrand Russell echoed the sentiment: “But for children, there would be no need of any institution concerned with sex,” he wrote.  “[I]t is through children alone that sexual relations become of importance to society, and worthy to be taken cognizance of by a legal institution.”

Not every marriage will produce children, but every child is the result of a male-female union—and needs a mom and a dad. Marriage exists to bring a man and a woman together as husband and wife to be father and mother to any children their union produces.

Marriage is society’s least restrictive means of ensuring the well-being of children. State recognition of marriage protects children. How? By encouraging men and women to commit to each other permanently and exclusively—and to take responsibility for their children.

Social science confirms the importance of marriage for children. According to the best available sociological evidence, children fare best on virtually every examined indicator when reared by their wedded biological parents. Studies that control for other factors, including poverty and genetics, suggest that children reared in intact homes do better than those who aren’t in categories such as educational achievement, emotional health, familial and sexual development, and delinquency and incarceration.

The statistics have penetrated American life to such a great extent that President Barack Obama refers to them as well known:

We know the statistics—that 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 twenty times more likely to end up in prison. They are more likely to have behavioral problems, or run away from home, or become teenage parents themselves. And the foundations of our community are weaker because of it.

Fathers matter, and marriage helps to connect fathers to mothers and children. But how could the law teach that fathers are essential if it redefines marriage to make fathers optional?

Redefining marriage would further distance marriage from the needs of children and deny the importance of mothers and fathers. It would deny, as a matter of policy, the ideal that children need a mother and a father.

Marriage laws work by embodying and promoting a true vision of marriage, which makes sense of those norms as a coherent whole. Law affects culture. Culture affects beliefs. Beliefs affect actions. The law teaches, and it shapes the public understanding of what marriage is and what it demands of spouses.

Indeed when the law redefined marriage by introducing no-fault divorce, it taught something about marriage: that it need not entail a real commitment to permanency. It used to be that divorce was issued for fault—the three A’s of common law: abuse, abandonment and adultery—but no-fault divorce allowed a spouse to divorce for any reason or no reason at all. And as a result divorce rates rose from single digits to nearly 50 percent.

And the costs were high.

A Brookings Institution study found that $229 billion in welfare expenditures between 1970 and 1996 can be attributed to the breakdown of the marriage culture and the resulting exacerbation of social ills: teen pregnancy, poverty, crime, drug abuse and health problems. A 2008 study found that divorce and unwed childbearing cost taxpayers $112 billion each year. Utah State University scholar David Schramm estimated that divorce alone costs local, state and federal governments $33 billion each year.

Marriage benefits everyone. Separating childbearing and childrearing from marriage burdens innocent bystanders: not just children, but the whole community. Often, the community must step in to provide (more or less directly) for their well-being and upbringing. By encouraging the marriage norms of monogamy, sexual exclusivity and permanence, the state strengthens civil society and reduces its own role.

By recognizing marriage, the government supports economic well-being. Here’s how W. Bradford Wilcox, a University of Virginia professor, described the benefits of marriage in summarizing a study he led as part of the National Marriage Project: “The core message…is that the wealth of nations depends in no small part on the health of the family.”

The same study suggests that marriage and fertility trends “play an underappreciated and important role in fostering long-term economic growth, the viability of the welfare state, the size and quality of the workforce, and the health of large sectors of the modern economy.”

So it should be no surprise that the decline of marriage most hurts the least well-off.

A leading indicator of whether someone will know poverty or prosperity is whether, growing up, he or she knew the love and security of having a married mother and father. A Heritage Foundation report last year by Robert Rector points out: “Being raised in a married family reduced a child’s probability of living in poverty by about 82 percent.”

And although all citizens have the right to live and love as they choose, no one has the right to redefine marriage for everyone.

Redefining marriage to exclude the norm of sexual complementarity (shared by a man and a woman) makes other marital norms optional and sabotages the reason for marriage policy. Again, the government’s interest is to ensure that relationships that could result in children are permanent and monogamous, so that those children have a mom and a dad.

Civil recognition of the marriage union of a man and a woman serves the ends of limited government more effectively, less intrusively and at less cost than does picking up the pieces from a shattered marriage culture.

-Ryan T. Anderson is the William E. Simon Fellow in Religion and a Free Society at The Heritage Foundation. He is co-author with Sherif Girgis and Robert P. George of the book “What Is Marriage? Man and Woman: A Defense” (Encounter, 2012).