A proposal to allow Massachusetts residents to list their gender as "X" on state IDs and driver’s licenses failed to pass in last night’s legislative session.

Though the RMV is already planning to implement a third gender option on state IDs, Senate President Karen Spilka told WGBH News she wants the option backed by the force of legislation.

“If it’s done administratively at any point in time, it can be undone administratively,” Spilka said. “I think it’s important for the legislature to also make a statement that we are an inclusive, welcoming state.”

Spilka, who introduced the legislation, says she plans to talk with the RMV, meet with Governor Charlie Baker, and file the bill again next session.

“I do believe that there are other ways to get this accomplished and it doesn’t matter how it gets done, as long as it gets done,” she said. “We need to let people be who they are in the commonwealth, I think that it’s really a big step for inclusion and for accepting people for who they are.”

The RMV’s timeline for the program is as yet unknown.

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