Supporters of the bill argued that it would help protect children from medical treatments they believe are risky, unproven and could carry long-term consequences. Several Democrats joined Republicans in voting for the bill.

“The people of Louisiana have made it clear that our children are worth fighting for,” State Representative Gabe Firment, the Republican who sponsored the bill, said in a statement.

Critics argued that the proponents’ stance defied the outlook of much of the medical establishment, and that the ban would deny young people access to care that could be medically necessary and beneficial to their well-being.

Republican lawmakers resuscitated the bill after a previous attempt failed at the committee level. Last month, in the Senate Health and Welfare Committee, Fred Mills, a Republican, cast the deciding vote that stopped the bill from advancing, for which he faced considerable backlash from right-wing activists.

“I relied on science and data and not political or societal pressures,” Mr. Mills, who is a pharmacist, said, according to The Associated Press. “I prioritized the value of the physician-patient relationship, I put my trust that the physicians in Louisiana know better than I do regarding how to treat these children, and I decided that this is such a small unique subset of medical needs of the entire population that I should not take away approved and appropriate medicinal options.”

This time, the bill was rerouted through a different committee in order to advance. In the Senate, Mr. Mills was the single Republican who voted against it.

If the measure becomes law, Louisiana would join 17 states that have enacted bans or severe restrictions this year on access to transition care for minors, all part of a broader effort by conservative lawmakers to regulate the lives of transgender or gender-nonconforming young people.

The Louisiana Legislature also recently approved bills that would restrict teachers from discussing gender identity and sexual orientation — a version of what critics have labeled “Don’t Say Gay” laws that have been enacted in other states — and limit students’ ability to have teachers and school officials refer to them by pronouns other than the ones associated with the sex on their birth certificates.

L.G.B.T.Q. advocates have criticized lawmakers for directing so much effort toward targeting a small population that has a painful history of being marginalized and mistreated.

The state has an estimated 4,000 transgender teenagers, according to a report published last year by the Williams Institute, an L.G.B.T.Q. research organization based at the law school of the University of California, Los Angeles.

And a report by the Louisiana Department of Health found that there had been no gender-transition surgeries performed on minors in the past several years. The agency, relying on Medicaid claims data from 2017 to 2021, reported that the number of young people receiving hormone treatments and puberty blockers was quite small, ranging from 21 to 57 children a year.

If the bill becomes law, it could mean transgender minors would have to forgo transition care or leave the state to find it. Under the terms of the bill, young people already receiving this treatment would be allowed to temporarily continue it to avoid an abrupt halt, but that window would close at the end of 2023.

In a similar circumstance last year, when lawmakers voted to exclude transgender students from school sports with a veto-proof majority, Mr. Edwards — who had also opposed that legislation — neither signed nor vetoed the bill, allowing it to become law. The bill, he said at the time, “was going to become law whether or not I signed it or vetoed it.”