A Christian conservative group opposed to gay marriage has asked an Illinois court to intervene in a case challenging the constitutionality of the state's gay marriage ban.

The Illinois Family Institute presented oral arguments Thursday in Cook County Circuit Court, the Chicago Tribune reported. Attorney Bryan Beauman argued that allowing the group to defend the marriage law would “even the playing field.”

More than two dozen gay and lesbian couples who wish to marry in Illinois but are unable because state law defines marriage as a heterosexual union filed the lawsuit challenging the law in May. Nine couples are represented by the ACLU of Illinois, while Lambda Legal is representing sixteen couples.

Beauman said the refusals of Illinois officials to defend the law in court creates “a more compelling reason to let the Illinois Family Institute in to assist in the case.”

Emily Nicklin, an attorney representing plaintiffs, disagreed, saying that the organization “doesn't meet the standard to intervene.” She said filing a “friend of the court” brief would be more appropriate.