In his recent inaugural address, President Barack Obama invoked the Declaration of Independence to advocate for gay marriage. Citing "the most evident of truths—that all of us are created equal," the president then equated modern gay rights activism to civil rights movements of the past. The comparison wasn't new, though it has never been made on such a prominent stage.

For those who support redefining traditional marriage, the logic is simple. In the president's language: "if we are truly created equal, then surely the love we commit to one another must be equal as well." And conversely, opposition to gay marriage could only be motivated by a discriminatory belief that we are not equal. The warning is clear: Beware lest you find yourself "on the wrong side of history"—and judged a bigot.

San Francisco Archbishop Salvatore Cordileone, a proponent of California's Proposition 8, lauded the president's concern for equality. "I honor the president's concern for the equal dignity of every human being, including those who experience same-sex attraction, who, like everyone else, must be protected against any and all violence and hatred." But, as the Archbishop points out, the issue is not as simple as the president's inaugural suggests: "the marriage debate is not about equality under the law, but, rather, the very meaning of marriage." Specifically, what marriage means for children.

What is conspicuously absent from the "civil rights" argument for gay marriage is an appreciation for the rights of children. Marriage exists to ensure children's rights to be reared, as much as possible, by both their father and mother. We privilege marriage not, primarily, to nurture adults who love each other. We privilege marriage to nurture the children who come from the relationship of a mother and father. Thus, marriage is not merely about spousal rights. It is also, if not primarily, about parental and societal responsibilities to children. Marriage advocate Maggie Gallagher puts it simply. Why does marriage matter? To create a bond strong enough that "a child's heart can rely upon it."

Redefining marriage to eliminate either a mother or a father erodes its purpose of protecting children. Decades of research show that children not raised by their married biological parents (e.g., divorced, step-parent, cohabiting) "have, on average, twice the levels of risk, twice as many problems." Although there are few scientifically rigorous studies on the effects of same-sex parenting, recent studies of larger samples suggest similar cause for concern.

In other countries grappling with gay marriage, concerns for children are front and center. Canadian ethicist Margaret Sommerville frames the issue as "whether to give priority to children's rights or to homosexual adults' claims."

And in France, a multi-party commission of the National Assembly rejected same sex marriage in 2006, on the basis that, "The best interests of the child must prevail over adult freedoms . . . even including the lifestyle choices of parents."

Now France's Socialist Party is on track to undo that commission's work and legalize same-sex marriage. In response, an estimated 350,000 French citizens marched through central Paris in opposition. Public opponents of the Socialist Party's agenda include the group Homovox: "French Gays Against Gay Marriage." One spokesman, Jean-Marc, a mayor of a small urb in France, summed up his opposition this way: "[T]he law I advise would be whatever's best for the child. One must favor what is best for the child. Nobody can deny, I believe, that it's best for a child to have a mother and a father who love each other as best they can." Another said simply, "it would be against the principles of equality to deprive some children of [a mother and a father]."

Proponents of gay marriage often call it the "civil rights issue of our day." Past civil rights' movements gave voice to those excluded from the public sphere. Until the debate over gay marriage includes genuine concern for the rights of children—the most vulnerable and voiceless in our society—the true civil rights issue of our day will remain undefended.

Jenet Jacob Erickson teaches in the School of Family Life at Brigham Young University. Her opinions do not necessarily reflect those of BYU.