A bill to restrict transgender athletes is fraught with potential legal problems, the Idaho attorney general’s office says.

“I have concerns about the defensibility of the proposed legislation,” assistant chief deputy attorney general Brian Kane wrote in an analysis of House Bill 500.

The analysis — made public Tuesday — comes as the controversial transgender athletics bill awaits a House vote, which could come as early as Wednesday.

Dubbed the “Fairness in Women’s Sports Act,” HB 500 would ban transgender girls and women from participating in girls’ and women’s school sports. Kane’s nine-page analysis outlines several possible pitfalls:

• By treating transgender girls and women differently than other people, the bill could violate the 14th Amendment’s equal protection clause.
• Excluding transgender girls and women from girls’ and women’s sports raises several questions. It’s unclear that transgender athletes would have a “meaningful opportunity” to play on men’s teams or co-ed teams. And it’s unclear whether transgender athletes — a “very small minority” of the population — substantially restrict girls and women from competing in sports.
• The bill creates a “whistleblower” provision that allows another athlete to dispute a competitor’s gender, perhaps in bad faith. “A school official could know that the student is making the claim for no other reason than to harass the athlete, but the school would be prohibited from taking action to punish or discourage such behavior,” Kane wrote.
• Transgender athletes would more likely be forced to “establish” their gender through an invasive medical examination. “The government’s interest in ensuring competition and opportunities for women to compete in sports would almost certainly fail to justify this disparate treatment and impact,” Kane wrote.
• The bill might — or might not — violate Title IX, the landmark federal law that ensures women equal opportunities to compete in sports. The U.S. Supreme Court is considering a case that could decide whether Title IX protections extend to transgender athletes; Attorney General Lawrence Wasden filed a court brief arguing against such an extension. Regardless, Kane wrote, it’s “advisable” to hold off on HB 500 until the Supreme Court rules.
• HB 500 would require the NCAA to follow Idaho’s law on transgender athletes, which could violate the Constitution’s interstate Commerce Clause. NCAA policy allows transgender girls and women to play on girls’ and women’s team after completing a year of hormone therapy.

Rep. Barbara Ehardt, R-Idaho Falls, the sponsor of HB 500, did not immediately respond to a request for comment.

The House State Affairs Committee passed HB 500 on a party-line vote last week, setting the stage for the pending House vote. Over two days, the preponderance of public testimony ran against the bill. ACLU Idaho pledged to file a lawsuit if HB 500 passes.

The attorney general’s office does not release its opinions to lawmakers — but lawmakers can and sometimes do make the documents public. House Minority Leader Ilana Rubel requested the report, and the Boise Democrat released it to reporters Tuesday.