Maine lawmakers on Monday overturned 20 of Governor Paul LePage's vetoes, but left in place a veto of a bill that sought to ban conversion therapy (also called “ex-gay” or “reparative” therapy) to minors.

LePage, a Republican, on Friday vetoed LD 912 – a bill that sought to ban therapies that attempt to alter the sexual orientation or gender identity of lesbian, gay, bisexual and transgender youth – making him the first U.S. governor to veto such legislation.

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.”

The Maine legislature approved the bill late last month. On Monday, the bill failed to reach the two-thirds majority needed to override LePage's veto, the Portland Pres Herald reported.

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.)