Voters in Washington state approved a measure barring transgender athletes from playing on girls sports teams, a major midterms loss for LGBTQ advocates in the normally blue state.
With about 80 percent of ballots counted Friday, approximately 57 percent of voters approved the measure while 43 percent opted against it, and opponents conceded defeat.
The initiative will require the prohibition of trans girls from "competing with and against female students."
Approval of the conservative measure in a state that normally votes Democratic stands in stark contrast to the otherwise disappointing November 3 midterm vote for Republicans.
Opponents of the measure included some doctors who said that it is "not backed by clinical guidelines, and would create unwarranted stress and harm for young girls."
Under the initiative girls who want to play sports must undergo a physical reproductive organ exam, or genetic and hormone testing.
More than half of states have enacted laws in recent years restricting the participation of transgender students in sports.
The US Supreme Court upheld state bans in June.
The measure in Washington state was considered among the most extreme of four total similar measures that passed in this week's election.
The others were in Arizona, Nebraska and Colorado.
Trans athletes have been the target of Republican lawmakers and anti-LGBTQ groups who argue that their participation in girls and womens sports is unfair.
Civil rights advocates have countered that such efforts scapegoat a very small group of people, most of them children, who already face discrimination and bullying.
Over half of transgender youth have had suicidal thoughts in their lifetime and 31 percent have made at least one suicide attempt, according to the American Academy of Pediatrics.
The Washington Interscholastic Activities Association, which governs school-linked youth sports in the northwestern state, said earlier this year it is aware of just 10 transgender middle and high schoolers who play sports, out of some 200,000 students competing statewide.
Libby Watson -- campaign manager of the group No Hate WA State, which advocated against the Washington measure -- cast the initiative as "deceptive" and a bid "by MAGA forces to target trans kids for their own political gain."
The results are a "disappointment," Watson said in a statement, but "the fight is not over."
"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," the advocate continued.
"We stand with you and will continue to fight for a day when you can play sports without controversy."