Same-sex marriage is a subject best left to lawmakers, state attorneys argued Monday in a Court of Appeals case that could shake Maryland's long-held view of matrimony.

In a court brief filed by the Maryland attorney general last week, the state defended Maryland's 1973 law defining marriage as a union between a man and a woman, but indicated openness to legislation that would pave the way for the legalization of same-sex marriage.

The court should defer to the Maryland General Assembly, "where competing policies and their complexities could be balanced," rather than "constitutionalizing a matter and removing it from the democratic process," reads the brief that outlined the case.

"The General Assembly is the proper forum to weigh these issues," said Robert Zarnoch, counsel to the General Assembly, during argument Monday.

Some lawmakers agreed the issue belonged to the General Assembly, but said it was resolved more than 30 years ago.

"The General Assembly already took this issue up, and the majority of people, Republican and Democrat, voted to declare that marriage is between a husband and a wife," said Senate President Thomas V. Mike Miller Jr. "If people want to change the law, they're welcomed to try. But I don't think the law will be changed by the General Assembly, and I don't think it should be changed by the courts."

The case arose in 2004, when nine gay couples and a man whose male partner had died filed suit in Baltimore Circuit Court against court clerks who had denied them marriage petitions. The plaintiffs, represented by the American Civil Liberties Union, argued that Maryland's marriage law is at odds with a state equality law prohibiting gender discrimination.

"The exclusion of same-sex couples from marriage violates the most fundamental guarantees of equality and liberty for all," said Kenneth Choe, who represented the 19 plaintiffs.

In January, Baltimore Circuit Judge M. Brooke Murdock ruled the marriage law was unconstitutional but stayed the effect of her decision.

The state contends that the discrimination argument doesn't apply because the ban on same-sex marriage burdens men and women equally. The plaintiffs' attorneys say that view is too broad.

"(The state's) primary argument is that men as a class and women as a class are treated equally, so there's no disparity," said Choe. "But if you look at it individually, it is discriminatory to say one man can't marry another man because of his gender, that one woman can't marry another woman."

Two federal courts and six appellate courts in other states have rejected the claim that restricting marriage to opposite-sex couples amounts to unconstitutional gender discrimination, the brief notes. The plaintiffs' attorneys said that Maryland has the case law to pad its argument.

Another brief filed by a Baltimore-based attorney on behalf of 10 Maryland lawmakers also urged the court to leave the issue in the care of the Legislature, but stopped short of condemning same-sex marriage.

Matt Paavola, the attorney, said his clients are ideologically diverse, but all agree that "when you have an issue of such sweeping social magnitude, it belongs to the elected officials."

"People keep calling me and asking, 'Why are you against gay marriage?' And I tell them, 'That's not it,'" Paavola said. "If there are going to be changes, elected persons should be making them."

Maryland lawmakers have made inroads into the area of gay and lesbian rights, though not as swiftly as the 19 plaintiffs — and the larger community they have come to represent — had hoped.

The General Assembly passed legislation banning discrimination on the basis of sexual orientation in 2001 and creating life partnerships for medical decision-making in 2005, while bills to constitutionally ban same-sex marriage have failed repeatedly.

"This history reflects the antithesis of anti-homosexual animus," the state's brief said.

The nine couples and one gay widower represented in the case said they don't want to win their right to marry piecemeal.

"That's so demeaning having to go back and ask the Legislature for incremental laws," said Lisa Polyak, who lives in Baltimore with her partner of 25 years, Gita Deane, and their two children. "I think this is a simple justice issue, and I think it properly resides in the courts."

Capital News Service contributed to this report.