CHICAGO – The conservative Illinois Family Institute and two suburban Chicago churches are seeking a judge’s permission to help defend the state’s ban on gay marriage, saying they should be able to intervene in a lawsuit filed by 25 gay and lesbian couples who want to overturn the 16-year-old law.

Two downstate county clerks received approval this summer to defend the law after Cook County State’s Attorney Anita Alvarez and Attorney General Lisa Madigan refused to do so, claiming the ban violates the Illinois Constitution’s equal protection clause. Now the IFI, Arlington Heights-based Church of Christian Liberty and Bensenville-based Grace Gospel Fellowship, say they should be able to intervene, too.

Cook County Circuit Judge Sophia Hall heard arguments Thursday on the IFI’s request.