OLYMPIA — A controversial new law requiring public school to provide comprehensive sexual health education in all grade levels may not take effect next week as planned.

Opponents of the new mandates expressed confidence Thursday that they have gathered enough signatures for Referendum 90, which is aimed at repealing the legislation.

They must submit signatures of at least 129,811 registered voters to the Secretary of State’s Office by June 10 — the date the new law is set to take effect — to earn a spot on the fall ballot.

Mindie Wirth of Bothell, who filed the referendum, said they had just under the required amount at the end of May, and petitions keep flowing in.

“We’re looking good. We’re excited. We need to get that cushion,” Wirth said, referring to the goal of turning in well over the minimum to account for duplicates and invalid signatures.

Parents for Safe Schools, the coalition behind the effort, plan to deliver petitions in the afternoon June 10.

Gov. Jay Inslee signed Senate Bill 5395 on March 27. Superintendent of Public Instruction Chris Reykdal requested the legislation.

It requires school districts to adopt or develop comprehensive age-appropriate sexual health education consistent with state standards.

It mandates a curriculum be available for instruction to students in grades six through 12 in the 2021-22 school year and then all grades, including kindergarten, beginning in the 2022-23 school year.

Under Senate Bill 5395, starting in fourth grade, and continuing through high school, a school’s curriculum should contain instruction in areas such as physiological development, choosing healthy behaviors, health care, developing meaningful relationships and affirmative consent.

Many schools in Washington already teach sexual health education. This new law ensures every school adopts a curriculum. And the new law does provide parents an opportunity to request their children be exempt from the classes.

This was one of the most controversial bills of the 2020 session. Hundreds of people — opponents and supporters — packed hearings as it wended through the Legislature. A similar bill failed in 2019.

Democrats used their majorities in the House and Senate to push it through over strong opposition from Republicans.

“This is about making sure younger children know what kind of touching is inappropriate, whether by peers or predators. It’s about helping older students recognize and resist abusive or coercive behavior. It’s about teaching all children to respect diversity and not to bully others,” Sen. Claire Wilson, D-Auburn, the prime sponsor of the legislation, said in March.

During session, opponents argued sex education should be restricted to upper grades and expressed concern it did not let parents and school boards decide what is taught.

By the time Inslee signed it, his office had received 9,850 messages opposed to the measure and 59 in support.

Foes immediately kicked into action.

The coalition behind Referendum 90 include the state Republican Party, the GOP caucuses in the House and Senate, Informed Parents of Washington, and the Family Policy Institute of Washington, based in Lynnwood.

“It was very clear to everybody during the session that there was a huge groundswell of opposition all across the state,” said Mark Miloscia, executive director of the Family Policy Institute and a former state lawmaker. “We knew there was a great anger against what was being proposed with this bill.”

Signature-gathering began slowly largely due to restrictions imposed statewide to blunt the spread of coronavirus. A stay-home order closed businesses and churches — two lucrative arenas for signatures — and limited everyone’s movement.

Wirth said petitions got mailed out and returned, some with a couple names on them. In late April, as access to churches improved, so did the collection.

People got creative and set up drive-through signing stations in church parking lots. Volunteers with masks and gloves put out petitions, people drove up, signed with their own pen and drove on. At one point there were 160 such sites, many on grounds of Catholic churches. As in-person services restart, petitions can be placed on tables at churches.

“This was truly a grassroots effort,” she said. “This issue is something that is extremely important to people.”