The lawyers on Friday filed a motion for a preliminary injunction in a lawsuit launched in July against the school boards in Orange, Indian River, Duval and Palm Beach counties. The 26-page motion contends that the law, passed this year by the Republican-controlled Legislature and signed by Gov. Ron DeSantis, "was enacted with the purpose to discriminate and has the effect of discriminating against LGBTQ+ students and those with LGBTQ+ family members."

It alleges violations of speech, equal-protection and due-process rights and pointed to steps that the school districts have taken to try to comply with the law (HB 1557).

"HB 1557, by design, deters speech by and about lesbian, gay, bisexual, transgender, queer, and questioning people in schools," the motion said. "To achieve this end, the law employs undefined terms that restrict an absurdly broad scope of speech and activity, casting a broad chilling effect and leaving school officials to draw arbitrary and discriminatory lines in their attempts to implement the law."

The law, which has drawn nationwide attention, prevents instruction on gender identity and sexual orientation in kindergarten through third grade and requires that such instruction be "age-appropriate … in accordance with state academic standards" in older grades.

Republican lawmakers titled the measure the "Parental Rights in Education" bill. Opponents labeled it the "Don't Say Gay" bill.

Opponents also have challenged the constitutionality of the measure in a federal lawsuit filed in Tallahassee against the State Board of Education, the Florida Department of Education, Education Commissioner Manny Diaz Jr. and several school boards. That case is pending.

The lawsuit against the school boards in Orange, Indian River, Duval and Palm Beach counties was filed July 25 in federal court in Orlando. It has been assigned to U.S. District Judge Wendy Berger, who was named to the federal bench by former President Donald Trump after serving as a state appellate and circuit judge.

Attorneys for the four school boards have not filed initial arguments in the case. But in the separate case filed in Tallahassee, Attorney General Ashley Moody's office has contended that the state has the right to set curriculums for public schools and disputed that the "Legislature acted out of animus against LGBTQ individuals."

"The bill reflects no governmental preference about what students should learn about sexual orientation and gender identity," the state's lawyers wrote in a motion to dismiss the case. "Those subjects must be taught appropriately and, for the youngest children, they may be taught by parents, not in public-school classroom settings. That is a legitimate (state) interest."

The plaintiffs in the Orlando lawsuit include Jen and Matt Cousins, the parents of four children in Orange County schools; Will Larkins, a senior at Orange County's Winter Park High School who is president of the school's Queer Student Union; David Dinan and Vik Gongidi, a married same-sex couple who have two children in Indian River County schools; and the non-profit CenterLink, Inc., which has members including LGTBQ community centers in Orange, Duval and Palm Beach counties.

They are represented by lawyers from the Lambda Legal Defense and Education Fund, Southern Legal Counsel, the Southern Poverty Law Center and the international law firm of Baker McKenzie.

In Friday's motion for a preliminary injunction, they raised a series of arguments, including that the law "impermissibly chills" speech in violation of the First Amendment and is unconstitutionally overbroad and vague.

They also cited steps that the school districts have taken to try to comply with the law. As an example, they wrote that the Duval, Indian River and Palm Beach school districts have reduced or eliminated LGBTQ-student support guides and anti-bullying guidance.

"In (the Palm Beach County district), professional development workshops on LGBTQ+ issues were suspended and, in many districts, books with LGBTQ+ characters for students in K-12 have been removed or are being reviewed under HB 1557," the motion said. "Teachers have been encouraged to avoid anything that might generate discussion about LGBTQ+ people and have been chilled from supporting LGBTQ+ students and student groups. And, organizations that have traditionally provided LGBTQ+ training and other services to schools are being blocked from completing their work."