A group of Illinois pastors filed a federal lawsuit Thursday challenging the state's new ban on sexual orientation conversion therapy for minors.

The legislation, signed by Gov. Bruce Rauner last August, made it illegal for mental health care specialists to perform conversion therapies on patients under the age of 18.

The group Pastors Protecting Youth, which filed the suit, argues that the new law "unconstitutionally restricts a young person's right to make personal choices regarding his or her own choice of sexual identity, as well as the pastors' right to free speech and the exercise of religion."

Proponents of the law, including the legislation's House sponsor state Rep. Kelly Cassidy (D-Chicago), say it protects youth from "pseudo-scientific and harmful measures" seeking to change their sexual orientation or gender identity.

Four pastors represented by attorneys at Chicago-based Mauck & Baker, LLC are named as plaintiffs in the lawsuit, according to the Windy City Times.

"These pastors want a court declaration saying the law does not apply to them," attorney John Mauck with Mauck & Baker told reporters at a news conference. "The law does not have any specific exemptions for pastoral counseling, so that's why we're seeking the court order protecting them, so they will not be charged with consumer fraud for their teachings that homosexual conduct is sinful.

"We also are representing young people who don't have a place in our courts but are struggling with their sexual identity and sexual conduct," he continued. "In particular, they need advice when they are young and their hormones are raging, and they are trying to form an identity. Pastors can help them and want to help them."

UPDATE (3:09 p.m.): The LGBT rights group Equality Illinois is reacting to the Pastors Protecting Youth's lawsuit. 

"We condemn this attack on a reasonable law that protects the physical and mental health of LGBT youth in Illinois," said Equality Illinois CEO Brian Johnson. "The law protects patients from harmful, coercive, and fraudulent treatments that attempt to change the unchangeable. Faith leaders remain free to say what they want from the pulpit, regardless of how misguided it may be, and the law and the state and federal Constitutions protect that right. That was not changed by this law."

He added: "The lawsuit is simply an attempt to set back the clock on the growing national recognition of the rights of lesbian, gay, bisexual and transgender Americans, an attempt that has failed in other states where lawsuits were filed against similar laws. Courts have unanimously rejected legal challenges to these laws, recognizing that the state has a duty to regulate medical and mental health providers to protect patients from harmful and fraudulent treatments."