Public schools are paying religious groups to speak to students, and the presentations aren’t always as secular as they claim, Slate reported today.

According to investigative journalist Katherine Stewart, some groups bent on spreading a sectarian message in public schools have discovered an “effective” way into what should be a secular setting.

“They come into public schools under the banner of substance abuse programs, character education, anti-bullying education, or sex education,” Stewart wrote. “Then they set aside the education and get down to the business of promoting a religious message, sometimes along with a partisan political agenda.”

Stewart highlights the work of the Chastity Project and its Catholic founder, Jason Evert. Canutillo High School in El Paso, Texas, brought Evert to speak to its students last fall, and although his presentation didn’t mention God by name Stewart argues that religion still influenced its content.

“[W]hat the students are left with is a stark view of intimate relationships that is grounded in Evert’s religious convictions and an endorsement of entrenched gender hierarchies,” she wrote. “In Evert’s worldview, girls and women are either ‘pure as snow, all chastity’ or ‘disrespecting themselves.’ Men and boys are lustful cads who can’t be blamed for treating ‘unworthy’ girls without respect or dignity.”

Evert also encouraged female students to purchase a “white candle” and allow their husbands to light it on their wedding night as “a sign of the purity that you’ve maintained from this day to the day he lifts your veil.”

She reports that Canutillo paid Evert’s $1,000 honorarium directly to a local Christian crisis pregnancy center.

It’s important to note – as Stewart does – that social science doesn’t back up Evert’s claims. There’s no evidence that people who remain virgins till marriage have more satisfactory relationships. And there’s plenty of evidence that abstinence-only sex education largely fails to prevent risky sexual behavior in teens.

Abstinence isn’t the only focus for religious speakers; science education and bullying have also provided them opportunities to spread a sectarian message to students. Miracle of Science says on its website that it offers “amazing free assemblies for select schools” that showcase basic science experiments for young learners. But it’s actually an arm of God Science, and its founder, Stephen Bruce Wilson, told Stewart that he uses “chemical demonstrations to convey how great our God is.”

One anti-bullying speaker even uses his rare genetic disease as a platform to spread religious, anti-abortion messages to public school students.

This isn’t a new trend. Public schools regularly court lawsuits by inviting religious speakers, and many promote messages that are grounded in doctrine rather than established social science.

In 2013, George Washington High School in Charleston, W.Va., invited Pam Stenzel to speak to students. Stenzel would, according to flyers disseminated by the school, educate them about “God’s plan for sexual purity.” Stenzel used her platform to tell students that if they took birth control, their mothers “probably hated them.” Believe in West Virginia, which describes itself as “a Christ-centered catalyst helping transform the economic, political, social and spiritual environment of West Virginia” funded Stenzel’s visit to the school.

Months later, Richardson High School near Dallas, Texas, invited Justin Lookadoo to speak to students on the subject of abstinence even though his professional website trumpeted his sectarian motivations. Lookadoo didn’t bother to create a secular presentation for Richardson students; instead, he informed them that “Somewhere between the modern church and the feminist movement, guys turned into pansies.”

There have also been incidents involving Secret Keeper Girl and True Love Waits, which are both evangelical pro-abstinence ministries.

Americans United has frequently taken action to stop these assemblies when they’re announced, something Stewart also notes in her piece. She interviewed AU Staff Attorney Ian Smith, who noted that AU receives complaints about these assemblies every year.

“Some speakers make it a point to keep the in-school presentation secular,” Smith remarked, “but others don’t even bother and just openly preach to the assembled students.”

Public schools should carefully vet speakers under considerations and remember that the U.S. Supreme Court has unwaveringly ruled that they may not promote sectarian messages to students.

Students should certainly learn about science, bullying and even human sexuality. But they’re legally entitled to hear accurate messages that are based on facts. The presentations Stewart documents simply don’t belong in public schools.