Lawmakers in Alabama and North Dakota on Thursday approved bans on transgender girls and women competing on sports teams that match their gender identity, joining a series of Republican-led states that have focused on a rapidly growing culture clash over restricting transgender athletes and prohibiting gender-affirming medical treatments this legislative session.

The North Dakota bill bars public elementary and secondary schools from “knowingly” permitting students to compete on sports teams exclusively for their opposite sex, but allows girls to play on boys’ teams. The measure now goes to Gov. Doug Burgum.

In Alabama, a similar bill passed the Senate on Thursday, but was sent back to the state’s House of Representatives for approval.

The bills are “consistent with the attacks that we’ve been seeing all across the country towards trans youth and really their families as well,” said Dillon Nettles, policy director for the American Civil Liberties Union of Alabama. “These bills are going to have severe negative consequences for the outcomes of trans youth, from their social development to even their ability to build relationships with their classmates and peers.”

Republican lawmakers in more than 30 states have introduced dozens of measures this legislative session that aim to ban transgender youth health care and limit their participation in society, the highest number of anti-transgender bills ever filed in a single year.

Three states — Mississippi, Arkansas and Tennessee — passed legislation barring transgender women and girls from competing on female sports teams earlier this session, while Gov. Kristi Noem, Republican of South Dakota, signed two similar executive orders after issuing a veto over a transgender athlete bill over concerns about vague language and the possibility of lawsuits. Last year, Idaho became the first state in the nation to pass a ban on transgender athletes, though a federal judge has temporarily blocked the law from going into effect.

Dozens of states, including Alabama and North Dakota, are also considering measures that would make it illegal for transgender minors to receive gender-affirming medical treatments or surgery. This month, Arkansas became the first state to enact such a law, after the Republican-controlled Legislature overrode a veto by Gov. Asa Hutchinson, a Republican, who condemned the law as “a vast government overreach” that could hurt Republicans politically.

Proponents of the transgender sports restrictions say they are necessary to ensure fair athletic competition for female athletes, but transgender-advocacy groups and sports organizations like the N.C.A.A. say the bills are based on inaccurate stereotypes and unfairly target transgender women and girls. The N.C.A.A. requires transgender female athletes to be on testosterone suppression treatment for a year before they can compete on a women’s team.

Advocates for L.G.B.T.Q. rights have pressed the organization to move events from states considering such laws and those that have passed them. On Monday, the N.C.A.A. issued a statement in response to the mounting number of bills, saying it was “committed to ensuring that N.C.A.A. championships are open for all who earn the right to compete in them.” But it stopped short of saying it would pull championships.