President Donald Trump’s Justice Department is continuing its investigatory crackdown on left-wing ideology in schools, homing in on one of the biggest blue states renowned for its activist teachers unions.

The DOJ announced an investigation into 36 Illinois school districts over whether they allowed parents to opt their children out of instruction involving sexual orientation and gender ideology (SOGI).

“What we’ve learned is that Illinois has a comprehensive sex education and LGBTQ education regime for its public schools, and it appears that it does not allow for parental opt-outs, so these are mandatory topics,” Assistant Attorney General for Civil Rights Harmeet Dhillon told Fox News in an exclusive interview.

“If the schools are mandating this and not allowing parents the opportunity to opt out of content that may be inappropriate for them based on religion or values, they would be afoul of that Supreme Court precedent,” Dhillon said. “And so we have reason to believe that these school districts in Illinois are not obeying the law, and we’re going to look into that.”

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The review will also examine whether districts are encouraging or facilitating student gender transitions without parental notice or consent, including through name and pronoun policies or school clubs focused on gender identity.

“This Department of Justice is determined to put an end to local school authorities keeping parents in the dark about how sexuality and gender ideology are being pushed in classrooms,” Dhillon wrote in a statement, announcing the investigation. “Supreme Court precedent leaves no doubt: parents have the fundamental right and primary authority to direct the care, upbringing, and education of their children.

“This includes exempting their children from ideological instruction that contradicts their values or decisions about their children’s health and best interests.”

The Dhillon-led Civil Rights Division announced Thursday it has opened investigations into the 36 public school districts to determine whether they have included SOGI content in any class from pre-K through 12th grade. If so, DOJ says investigators will examine whether schools notified parents of their right to opt their children out of that instruction.

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The Illinois school districts are recipients of hundreds of thousands of dollars of taxpayer funding, which could be at risk if civil rights violations are found.

Dhillon told Fox News the inquiry will go beyond classroom instruction and examine whether districts are encouraging or facilitating gender transitions without parental notice or consent, including through policies involving students’ names, pronouns or participation in school clubs focused on gender identity.

“Illinois is just pushing these radical agendas,” Dhillon told Fox News, adding that school districts are often left “in a rock and a hard place” and that federal court intervention may be necessary to “stop this illegal practice.”

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The DOJ said the investigations will also assess whether the districts limit access to single-sex intimate spaces — including bathrooms and locker rooms — and girls’ sports teams based on biological sex. The department said the districts under review receive federal funding and will be examined for compliance with Title IX and Supreme Court precedent on parental rights.

“Children have rights and parents have rights, and we’re here to enforce those rights,” Dhillon vowed to Fox News.

The districts named by DOJ include Atwood Heights School District 125, Bloomington Public Schools District 87, DeKalb Community Unit School District 428, Elmwood Park Community Unit School District 401, Freeport School District 145, Noble Network of Charter Schools, North Chicago Community Unit School District 187, Oak Lawn-Hometown School District 123, Reavis Township High School District 220, Thornton Fractional Township High School District 215 and Will County School District 92, among others.

The probe marks the latest development in federal scrutiny of Illinois education policy. Last year, federal officials opened a Title IX investigation involving the Illinois Board of Education and Chicago Public Schools over allegations tied to policies allowing transgender students to access bathrooms and locker rooms consistent with their gender identity.

Fox News’ Mike Tobin contributed to this report.