Gender Justice League, a Seattle-based LGBTQ advocacy group, told KUOW on Thursday that it may challenge the ban on privacy grounds, though the group has yet to formally announce a lawsuit.

“We are having active conversations with our partners and also evaluating what legal options are available to us. If there is an avenue, we will challenge this ballot measure in court on behalf of our members and our community and trans youth,” said Danni Askini, the group’s executive director.

She said Gender Justice League would challenge the measure, Initiative 638, based on a 2008 student privacy rights case that ruled that Washington schools requiring suspicionless urine testing of students was unconstitutional.

“We believe that the Washington constitution and the Supreme Court have been really clear that I-638 would go far beyond a random drug screening and invade all girls’ privacy,” Askini said, adding that the measure “sets a really chilling and disturbing precedent.”

Washington’s ban, which is set to go into effect on Dec. 3, the deadline for the Secretary of State to verify election results, currently has 57% of the vote. Though thousands of votes were left to tally on Thursday, the Associated Press called the race Wednesday evening.

The ban would require girls to obtain a genital exam, a hormone test, or a chromosome test to verify their birth sex before they could participate on a girls’ school sports team. It would be a philosophical shift for Washington state, which for nearly 20 years has allowed students to participate on sports teams that align with their gender identity.