DES MOINES, Iowa (AP) – A gay rights organization filed legal arguments April 4 in a case that will decide the constitutionality of the state’s ban on same-sex marriage.

New York-based Lambda Legal, which has spearheaded a same-sex marriage drive across the country, filed the arguments in a lawsuit on behalf of six gay and lesbian couples from Iowa who were denied marriage licenses, as well as three of the couples’ children.

An initial lawsuit was filed in Polk County District Court in 2005, naming former Polk County recorder and registrar Timothy Brien.

That lawsuit prompted a ruling last August by Judge Robert Hanson, who said the state law allowing marriage only between a man and a woman violates the constitutional rights of due process and equal protection.

The judge said the state law banning same-sex marriage must be nullified, severed and stricken from the books and that the state’s marriage laws must be rewritten to become gender neutral.

A day later, Hanson stayed the decision, but only after more than 20 same-sex marriage applications had been accepted and one couple, Sean Fritz and Tim McQuillan of Ames, were married. They had obtained a judge’s waiver of Iowa’s three-day waiting period for marriage licenses.

The case is now before the Iowa Supreme Court.

Critics said the ban, approved by lawmakers in 1998 and known as the Defense of Marriage Act, contradicts previous court rulings regarding civil rights and should be struck down. Its supporters said marriage should be defined as between a man and a woman only.

Roger J. Kuhle, an assistant Polk County attorney, told The Associated Press on April 3 that he would not be able to see the arguments filed by Lambda Legal until after the weekend. He has said in the past that the issue should not be for a judge to decide, but should be left to lawmakers.

In the arguments filed April 4, Lambda Legal maintains that the ban denies gay and lesbian couples the constitutionally guaranteed right to liberty and privacy and equal protection under the law.

Lambda Legal argues that civil marriage in Iowa “is the only gateway” to rights, obligations and benefits that protect married couples and their children.

Some of the examples it listed were the authority to make health care and burial decisions, entitlement to workplace and other benefits from spouses and the ability to file joint tax returns and take marriage-related deductions.

“But marriage is not merely a bundle of legal rights and duties,” the arguments said. “For two people who have found joy in each other, it can be a definitive expression of love, devotion, and dedication. It allows each to honor the relationship of one to the other in a state-sanctioned way.”

In time for Friday’s deadline, at least 16 “friend of the court” briefs were expected to be filed in support of the gay and lesbian couples’ lawsuit, Lambda Legal said in a news release.

Among those briefs was one signed by former Iowa lieutenant governors Sally Pederson and Joy Corning. The women released a statement on Friday saying that they believe the courts, not lawmakers, should decide the issue.

“We have a keen understanding of the different roles the courts and Legislature play in leading our state and treating all Iowans with fairness,” they said in the statement.

The gay couple that was married in Iowa, Fritz and McQuillan, issued a statement about the “friend of the court” briefs filed in support of the lawsuit. They are not among the plaintiffs in the case.

“We are humbled by the amount of support that our fellow Iowans are lending to the case. They reflect the views of many Iowans, including those of our families, our friends, and our community,” they said in the statement.

Lambda Legal said nine “friend of the court” briefs were filed on behalf of Brien. The deadline for those was earlier this year.

Chuck Hurley, president of the Iowa Family Policy Center, which supports the same-sex marriage ban, said the issue was decided by the Legislature and should not have been overturned by a judge.

“I think that the core issue before the court is will they respect the public policy decision-making authority of the Legislature?” he said. “The Legislature spoke, it was signed by the governor in 1998, and now one judge has overturned that.”

Oral arguments will be scheduled by the Supreme Court in coming months, but a decision this year is unlikely.