The Senate on Thursday voted 34-0 to ban the use of conversion therapy to change the sexual orientation or gender identity of minors, with five Republicans voting "present" rather than for or against the bill.

Sen. Vinny deMacedo said he and Sens. Bruce Tarr, Ryan Fattman, Donald Humason and Dean Tran oppose conversion therapy but have concerns that the bill's wording is vague and infringes on the rights of mental health professionals.

He said the bill "provides too much room for interpretation in an area that requires caution and precision."

Tarr, the minority leader, had proposed asking the Supreme Judicial Court to advise the Senate on whether the bill (S.2187) was constitutional. Democrats beat back that attempt on a 32-6 party line vote.

"We are confident that the pending bill is constitutional," Senate Rules Committee Chair Joan Lovely said. "It relies on well-established authority of the state to regulate professional conduct."

Sen. Patrick O'Connor of Weymouth, the sixth member of the GOP caucus, voted for the ban.

The House approved its conversion therapy ban 147-8 earlier this month.