Maine Governor Paul LePage, a Republican, on Friday vetoed a bill that sought to ban therapies that attempt to alter the sexual orientation or gender identity of lesbian, gay, bisexual and transgender youth.

Such therapies go by names such as “conversion therapy,” “reparative therapy” or “ex-gay therapy.

LePage said that the legislation was unnecessary and that he had “grave” concerns that the bill could be interpreted “as a threat to an individual's religious liberty.”

“No evidence has been presented during the many public meetings on this subject that indicates that conversion therapy is being used by anyone, including licensed professionals, in the State of Maine,” LePage wrote in vetoing the bill.

“Parents have the right to seek counsel and treatment for their children from professionals who do not oppose the parents' own religious beliefs. At no time should such treatment take the form of mental or physical abuse and such treatment should always be subject to the statutory requirements of the standard of care for that profession,” he added.

The Maine legislature approved the bill late last month. LePage is the first U.S. governor to veto such a bill.

Similar legislation has been enacted in New Hampshire, Hawaii, Maryland, Washington, Connecticut, California, Nevada, New Jersey, Oregon, Illinois, Vermont, New York, Rhode Island, New Mexico and the District of Columbia. Lawmakers in Delaware have approved a similar bill.

(Related: UK government announces plan to ban “ex-gay” therapy.)