A Cook County, Illinois judge ruled Friday that a lawsuit challenging the state's ban on gay marriage can proceed.

Circuit Judge Sophia Hall denied a motion to dismiss the lawsuit after hearing oral arguments in the case on August 6.

Plaintiffs in the suit are twenty-five gay and lesbian couples who requested marriage licenses in Cook County, which includes Chicago, but were denied.

Illinois currently recognizes gay couples with civil unions but a state law limits marriage to heterosexual couples.

A marriage bill stalled in the House after passage in the Senate on Valentine's Day. Activists are lobbying for a final House vote during the upcoming fall session, but the bill's champion in the House, Rep. Greg Harris, has signaled that he's considering tabling the bill until next year.

(Related: Illinois gay marriage bill might not see House vote this year.)

The socially conservative Thomas More Society intervened to defend the state's marriage laws after state officials refused to do so. Opponents argued that gay couples are not harmed by the law because they have the option of marrying in 13 other states plus the District of Columbia.

“Nothing in Windsor suggests that the availability of the federal benefits of marriage would be lost if a same-sex couple validly married in one State moved (or returned) to a State that does not allow or recognize such marriages. Thus, those plaintiffs who were lawfully married in another State (or who would marry in another State) may be eligible for all the federal benefits of marriage, regardless of the fact that Illinois does not allow or recognize such marriages (other than as civil unions),” lawyers for the Thomas More Society wrote in their brief.