Headed up by Sens. Kirk Dillard and Bill Haine, 11 members of the state's General Assembly have filed an amicus curiae brief in support of the ban on same-sex marriage. The 19-page document argues that the ban is constitutional and that lawmakers, not courts, should determine the fate of the law.

"Since there is no clear constitutional support for a right to same-sex marriage in Illinois, a judicial ruling that such is required in the State would clearly contravene the principal of separation of powers, giving precedence to the opinions of the judiciary over the enumerated provisions of the constitution," the brief reads.

The document goes on to argue that children are better off raised by heterosexual parents and that religious institutions could face persecution if same-sex marriage were made legal. The brief references recent opposition by Mayor Emanuel and Ald. Proco Joe Moreno to the construction of a Logan Square Chick-fil-A after the chain's COO made anti-gay comments, as an example.

Both the American Civil Liberties Union and Lambda Legal filed lawsuits on behalf of 25 same-sex couples that want to marry in Illinois. While the suits name Cook County Clerk David Orr, Orr and State's Attorney Anita Alvarez have refused to defend the ban. Illinois Attorney General Lisa Madigan has also intervened in support of same-sex marriage.

The brief supports a motion to dismiss the cases filed by conservative law firm Thomas More Society on behalf of two intervening county clerks. Circuit Court Judge Sophia Hall must approve the motion before it becomes part of the case.

Thomas More Society praised the filing in a press statement, noting that the Catholic Conference of Illinois has also filed a brief in the case that argues against marriage equality.

The lawmakers that submitted the brief include Sens. Matt Murphy, Bill Brady, Darrin LaHood; Reps. Richard Morthland, Paul Evans, Michael Connelly, David Reis, Joseph Lyons and Patti Bellock.