Utah Gov. Spencer Cox became the second Republican governor in the past week to veto a bill that would have barred transgender athletes from competing in girls’ sports, writing an impassioned letter to state GOP leaders on Tuesday explaining his decision.

Cox cited “fundamental flaws” in the legislation, known as H.B. 11. But chief among the governor’s concerns were the mental health impacts such a bill could have on transgender youths in the state, he wrote.

Cox’s decision to veto the bill highlights divisions within the Republican Party on the efficacy and morality of bills restricting the lives of young trans people. GOP leaders in Utah said they plan to override Cox’s veto, which would require approval from two-thirds of the state’s lawmakers.