BOISE, Idaho (AP) — An appeals court on Monday will consider the constitutionality of the first law in the nation banning transgender women and girls from playing on women's sports teams.

The 9th U.S. Circuit Court of Appeals will hear arguments in the case that will likely have far-ranging consequences as more states follow conservative Idaho's lead.

Idaho passed its law last year, and more than 20 states have considered such proposals this year. Bans have been enacted in Alabama, Arkansas, Mississippi, Tennessee and West Virginia. Florida lawmakers passed a bill, and South Dakota’s governor issued an executive order.

On Monday, conservative Republican lawmakers in Kansas failed to override Democratic Gov. Laura Kelly’s veto of a proposed ban on transgender athletes in girls’ and women’s school sports.

Supporters say such laws are needed because transgender female athletes have physical advantages. Opponents say the law is discriminatory and, in Idaho, an invasion of privacy because of the tests required should an athlete’s gender be challenged.

Lawmakers in Idaho have argued that allowing transgender athletes on girls’ and women’s teams would negate nearly 50 years of progress women have made since the 1972 federal legislation credited with opening up sports to female athletes.

The state's law prohibits transgender students who identify as female from playing on female teams sponsored by public schools, colleges and universities. It does not apply to men’s teams.

The American Civil Liberties Union and Legal Voice women’s rights group sued last year over the Idaho law, contending it violates the 14th Amendment’s Equal Protection Clause because it is discriminatory.

A federal judge temporarily blocked the law from taking effect, and Idaho appealed in September.