Two gay men have filed a lawsuit challenging a controversial Tennessee law that allows mental health therapists and counselors to turn away LGBT clients.

The law, signed in April by Republican Governor Bill Haslam, states that counselors can refuse to treat clients based on their “sincerely held principles,” a change from the bill's original language of “sincerely held religious beliefs.”

Opponents say the measure could negatively impact young LGBT people.

According to Reuters, Bleu Copas and Caleb Laieski filed their lawsuit on Tuesday in the Chancery Court for Anderson County. The men argued that the law violates the Tennessee Constitution and the U.S. Constitution's 14th Amendment.

LGBT persons were the target of the statute. They are singled out for discriminatory treatment. There is no other group which could conceivably be the target of the statute,” the suit reads in part.

In signing the law, Haslam, who is named as a defendant in the suit, said that he thought it “reasonable to allow these professionals to determine if and when an individual would be better served by another counselor better suited to meet his or her needs.”

(Related: Counseling association cancels Tennessee conference over anti-gay bill.)