NASHVILLE (AP) — Tennessee's GOP-dominant Senate advanced legislation Monday that would ban transgender athletes from participating in girls' sports.

The bill has been heavily criticized by Democrats and civil rights advocates, who have warned that Tennessee will likely face costly legal challenges if signed into law, pointing to a similar measure in Idaho that's currently blocked from being enacted as opponents argue it's unconstitutional in court.

However, despite threats of pending litigation, nearly a dozen states this year have lawmakers backing restrictions on athletics or gender-confirming health care for trans minors this year. Briefly, it appeared Tennessee might waffle in its own attempt after Senate Speaker Randy McNally said the bill may not be necessary due to the lack of transgender student athletes competing in Tennessee sports. However, he later came out in support of the legislation.

"This bill is about guaranteeing safety and a level playing field for girl athletes on middle and high school team," said Sen. Joey Hensley, a Republican from Hohenwald.

Hensley later told the chamber that he did not talk to any transgender individuals while drafting the bill.

"Supporters of SB228 never produced evidence that there is a need for this legislation," Chris Sanders, executive director of the Tennessee Equality Project, which promotes LGBTQ rights. "It never was about sports. It was always about discrimination against transgender students."

According to the bill, student athletes would be required to prove that their sex matches that listed on the student's "original" birth certificate in order to participate in public school sports. If a birth certificate is unavailable, then the parents must provide another form of evidence "indicating the student's sex at the time of birth."

"In passing this, we're not going to help a single kid," said Senate Minority Leader Jeff Yarbro, a Democrat from Nashville. "We're going to make life harder for kids whose lives are already difficult."

After passing the Senate, the bill must now clear the Republican-controlled House, which is likely according to House Speaker Cameron Sexton.

Republican Gov. Bill Lee has held off promising he'll sign the bill should it land on his desk, but he has said that transgender athletes would " destroy women's sports " and stressed that transgender athletes would put "a glass ceiling back over women that hasn't been there in some time."