A divisive school bathroom bill cleared the Senate Thursday afternoon on a party-line vote.

Senate Bill 1100 requires schools to regulate bathroom and locker room use based on a patron’s gender assigned at birth. Overnight accommodations and alternative dressing rooms also fall under the bill’s purview. The bill does allow students who are “unwilling or unable” to comply with the legislation to obtain an accommodation from their school.

Exemptions can be made available for medical emergencies, janitorial needs, natural disasters and safety emergencies.

Bill sponsor Sen. Ben Adams, R-Nampa, said SB 1100 will guarantee a safe learning environment for students.

“The truth is the truth: men and women are different,” Adams said.

But Senate Democrats said the bill excludes intersex individuals, who might be unable to comply with a binary bathroom arrangement. And Sen. Melissa Wintrow, D-Boise, said the bill will be difficult to enforce.

“We’re not going to ask people to carry their birth certificates around,” Wintrow said. “This bill is unnecessary and it’s harmful.”

Opponents also said the bill’s cause of action clause is too harsh, and could result in unwarranted lawsuits against school districts or district personnel.

Republican senators sided with Adams.

Sen. Brian Lenney, R-Nampa, said school superintendents around the state are asking for guidance on hot-button issues, including transgender bathroom use. Some called on the Legislature to take action on the subject after a proposed policy ignited controversy at a January Caldwell School Board meeting.

Caldwell’s policy would have allowed students to use the bathroom aligned with their gender identity, rather than biological sex. It has since been sidetracked.

And the private action clause, according to Lenney, is necessary.

With the 28-7 vote, the bill is headed to the House.