Washington Initiative 638 passed, The Associated Press declared Wednesday evening. Starting Dec. 3, the measure will bar most transgender girls from girls’ school sports. It will also require sex verification for students joining those teams. “The effective date of the initiative is December 3, 2026,” the state’s fiscal impact statement says.
No Hate in WA State, the campaign against the measure, called the result a “disappointment” in a statement Wednesday evening, KUOW reported. “To all trans girls participating in school sports in Washington, we want you to know that you belong: on the field, on the court, on the team,” campaign manager Libby Watson said. “We stand with you and will continue to fight for a day when you can play sports without controversy.”
“This would generally prevent transgender girls from participating on girls’ sports teams,” the explanatory statement in the state voters’ pamphlet says. The verification has to be signed by “the student’s personal health care provider,” according to the initiative’s text.
Brian Heywood, the conservative hedge fund manager who founded Let’s Go Washington, spoke on election night while results were still unofficial. “I think this is a big bellwether for the state,” Heywood said, according to OutKick.
Opponents made their case in the voters’ pamphlet. “We all want fairness and safety in sports, but this poorly written measure would require girls as young as 8 to undergo intrusive medical sex certification as a new part of sports physicals,” they wrote.
When Washington Initiative 638 Takes Effect, and Who It Covers
A voter-approved measure “shall be in operation on and after the thirtieth day after the election at which it is approved,” Article II of the Washington Constitution says, which lands on Dec. 3. “The provisions of the initiative apply prospectively, not retroactively,” the fiscal statement adds.
The rule covers public K-12 schools and private schools that compete through the Washington Interscholastic Activities Association or a similar group, the explanatory statement says. “These requirements apply to girls only, boys are exempt,” opponents wrote.
About 118,000 girls play high school sports in Washington, KIRO 7 reported, citing WIAA numbers, and the WIAA told The 19th it knew of about 10 trans middle and high schoolers who play sports. “All the governing bodies on this topic say that we should be limiting our genital exams for our girls,” Kelsey Gellner, who opposed the measure, told KIRO 7.
What I-638 Requires for Sex Verification
Supporters insisted the sex check would ride along with routine care. “Don’t be misled by the opposition. IL26-638 doesn’t require invasive or expensive exams,” they wrote in the pamphlet.
Their argument says a provider would verify sex “based on the student’s birth records, medical history and/or a standard, non-invasive physical examination.” The initiative’s text requires a provider’s statement that verifies biological sex “relying only on one or more of the following” criteria.
“The verification would have to be based on the student’s reproductive anatomy, genetic makeup, or normal endogenously produced testosterone levels,” the explanatory statement says. Opponents put it more bluntly in the pamphlet. “It bans parents from using birth certificates,” they wrote.
“Students would thus have to undergo some type of medical evaluation of their sex to participate in interschool sports designated for female students only,” according to the explanatory statement.
The Office of the Superintendent of Public Instruction expects a one-time cost of about $21,000 to update its guidelines, the fiscal statement estimates. “Local school districts would likely also incur costs to revise existing policies, procedures, rules, and other requirements, but this fiscal impact is indeterminate,” it says.
Let’s Go Washington vs. No Hate in WA State
Heywood filed the initiative in June 2025, OutKick reported, and backers turned in more than 440,000 signatures, according to The 19th. “This was citizens who are voting very blue still in a lot of ways saying, hey, it’s not a Republican/Democrat issue, it’s a parental issue, it’s a fairness in girls sports issue,” Heywood said election night. Asked by KUOW whether he had talked with transgender students about the measure, he said he had not. “It wasn’t about transgender students. It was about girls,” Heywood said.
Lawmakers let the 2026 session end without a hearing, which sent it to voters, Gayety reported in October. “This policy was not from the kids,” Rep. My-Linh Thai, a Bellevue Democrat, told The Seattle Times before the vote.
No Hate in WA State cited Gov. Bob Ferguson and U.S. Sen. Patty Murray as opponents of I-638, KIRO 7 reported. “Today, students remain fully clothed during sports physicals,” opponents wrote in the pamphlet.
No Hate in WA State raised a little more than Let’s Go Washington, which also backed the “parents’ rights” Initiative 1 and a millionaires tax repeal, KUOW reported. Frances Staudt, a Tumwater High student who helped collect signatures, told Let’s Go Washington’s watch party Tuesday night that “Washington people have had enough,” OutKick reported.
On June 30, the U.S. Supreme Court upheld West Virginia’s and Idaho’s bans on trans girls in girls’ sports 6-3, with Justice Brett Kavanaugh writing that “safety and competitive fairness” are important government interests, JURIST reported. Colorado, Nebraska and Arizona voters weighed trans athlete measures this week too, Yahoo News reported, and Gayety’s election results hub is tracking them.
Does I-638 Clash With Washington’s Law Against Discrimination?
Washington’s Law Against Discrimination folds “gender expression or identity” into its definition of sexual orientation, covering identities that differ from what’s “traditionally associated with the sex assigned to that person at birth,” RCW 49.60.040 says. The WIAA has let trans students compete in line with their gender identity since 2007, The 19th reported.
A school law, RCW 28A.642.010, bars discrimination in public schools based on “sexual orientation, gender expression, gender identity,” among other traits. I-638 leaves that law alone and rewrites a different one so school sports run “without regard to sex, except as provided in section 3 of this act.”
Andrew Villeneuve, executive director of the Northwest Progressive Institute, said before the vote that I-638 would likely be challenged in court and could be struck down under the state constitution for holding girls to different requirements than boys, The Seattle Times reported. Lawmakers in Olympia can amend a voter-approved law within two years only “by a vote of two-thirds of all the members elected to each house,” the constitution says.
Lawyers for the ACLU of Washington have signaled they will fight I-638 in court, KUOW reported. “Washington state now has one of the worst anti-LGBT, anti-trans initiatives, truly, in the entire country,” state Democratic Party Chair Shasti Conrad said Wednesday, before the AP’s call.
