The battle over transgender rights has flared at the State Capitol as a group of Republican legislators unveiled a proposal Wednesday that would require people to use bathrooms and changing rooms that match their “biological sex.”

Joined by a handful of constituents and fellow legislators who support the bill, Rep. Glenn Gruenhagen, R-Glencoe, said he has been made aware of incidents in which transgender Minnesotans have tried to use bathrooms that didn’t match their biological sex.

“The bill protects the privacy and public safety of adults and young people, both in our society and in our schools,” Gruenhagen said at a news conference.

The measure would govern the use of public restrooms, locker rooms and dressing rooms.

Gov. Mark Dayton on Wednesday decried the legislation, saying that he was “appalled” and that he would veto it if it were to reach his desk. “This is about pandering to their extreme issue,” Dayton said.

He added: “They just keep bashing people for their own political advantage. … They’re wrong on the issue, and they’re wrong on the morality.”

Gruenhagen said the legislation was prompted by a complaint from a female constituent in his district who he said works in the Twin Cities. The third-term Republican said his constituent felt uncomfortable after a transgender co-worker began using the women’s restroom at their workplace.

“My constituent is afraid to protest too much because she believes her job would be at risk,” Gruenhagen said.

The legislation has not been scheduled for a committee hearing. Similar legislation failed to advance last year in the Legislature.

State Sen. Scott Newman, R-Hutchinson, the lead Senate sponsor of the proposal, said the bill is “controversial” and described the many phone calls his office has received on the topic. He said the response by the transgender community convinced him that they are “not the bullied. They are the bullies.”

Monica Meyer, executive director of OutFront Minnesota — an advocacy group for lesbian, gay, bisexual and transgender individuals that opposes the legislation — criticized the rhetoric by GOP legislators, saying it “creates a hostile climate in our state.”

She added: “Elected officials should be looking at policies that improve our state for all people.”

Star Tribune staff writer J. Patrick Coolican contributed to this report.