Maintaining marriage as a union between a man and a woman is a matter of social justice, said Ryan Anderson, a political scholar and editor of the online journal Public Discourse, in a recent talk.

Speaking to students at Georgetown University in Washington, D.C., Anderson acknowledged that efforts to redefine marriage are often characterized as being rooted in a sense of justice.

However, he said, the case against redefining marriage is actually an argument based upon justice, "precisely because marriage exists as the prime institution of social justice that guarantees and protects the rights and well-being of children."

"If you care about social justice and you care about limited government; if you care about the poor and you care about freedom – it's better served by a healthy marriage culture than by government picking up the pieces of a broken marriage culture."

Anderson, a Ph.D. candidate in political philosophy at the University of Notre Dame, is also co-author of the book, "What Is Marriage? Man and Woman: A Defense."

Determining marriage's definition and limits is the primary concern of the marriage debate, Anderson said in his Oct. 9 talk.

"Everyone wants marriage equality: we all want the government to treat all marriages as equal, but that begs the question – what is marriage?

He explained that many of those who promote the redefinition of marriage to include same-sex couples understand marriage to be an intense kind of romantic relationship between sexual partners. In this view of marriage, adult desires and sexual needs are of primary concern, and the needs of children produced by such a union are secondary.

However, this understanding of marriage is lacking, Anderson said, as it does not take into account the needs of children, "nor can it describe or define or defend" the norms surrounding marriage, such as why government is involved in it; its restriction to two people; why it is sexual; and why it should be permanent.

This understanding of marriage "makes it more about the desires of adults and less about children" and their needs, said Anderson, adding that "the consequence of redefining marriage is that more people will think of their relationship in those terms and that it will produce bad social outcomes, especially for children."

But across diverse societies and throughout history, he contended, marriage has been understood as a "comprehensive union" in which man and woman become "one flesh," particularly in their ability to create children. As a whole, in this understanding, "marriage is ordered to the comprehensive good in the creation and raising of children."

This understanding is also "based on the social reality that children deserve a mother and a father" and that "there's something about gender that matters" in the raising of children.

"There is no parenting in the abstract: there is mothering and there is fathering," he said, and both mothers and fathers "bring different gifts" to children.

He pointed to studies examining socio-economic factors, which show that children raised by their biological mothers and fathers fare better than those raised by other family structures, particularly same-sex parents.

In addition, Anderson observed that "the breakdown of the family" in the latter half of the 20th century was accompanied by a rise in social dysfunction, marked by a widespread number of indicators ranging from school performance to crime rates to decreased adult happiness. These indicators show a marked correlation with fatherlessness rates in the home.

Mothers are always present at a child's birth, the scholar continued. "The question for culture is whether a father will be present, and if so, for how long?"

"If you redefine marriage in law, there will be no institution left that even holds as an idea the right of a child to have a relationship with both a mother and a father."

Such a redefinition "holds up in law that men and women are functionally interchangeable" thus preventing the law from teaching "that fathers are essential." Rather, it "will make fathers optional," likely compounding the already-existing consequences of fatherlessness in society.

"If you care about the poor, what can we do to make it more likely that these men commit to the women that they are in relationships with, and then take responsibility for the children that they create?" Anderson asked.

"The reason why the state is in the marriage business is to maximize the opportunity that every child will be raised by a mother and a father, and preferably by the mother and the father that created the child," he said.

"The state wants to ensure that a man and a woman commit to each other as husband and wife, permanently and exclusively," he stressed, "and when this doesn't happen, the social costs run high."