Many of America’s public schools are teaching youths “pornographic” subject matter these days, some parents argue, so they’re planning a “Sex Ed Sit Out” on April 23.

They want like-minded parents to keep their children at home that Monday, to send a message to local school boards and elected officials.

Cities planning to participate include Charlotte, N.C.; Sacramento, Calif.; Bloomington, Ind.; Austin and San Antonio, Texas; Spokane, Wash.; and Martinsburg, W.Va., the Washington Times reported.

The effort is being run in partnership with socially conservative groups such as the Family Research Council, the American Life League and the Liberty Counsel, the Times reported.

One of the sit-out organizers is Elizabeth Johnston, a North Carolina blogger who calls herself “The Activist Mommy.” She first revealed plans for the sit-out during a radio interview April 4, the Christian Post reported.

Johnson contends that sexual content in some schools’ classes goes beyond the sex education class and into other subjects, such as history, science and math.

"We send our kids to school to learn reading and writing and science and history, not how to question whether they really are a boy or a girl,” Johnston told CBN News.

"We send our kids to school to learn reading and writing and science and history, not how to question whether they really are a boy or a girl." — Elizabeth Johnston, "The Activist Mommy"

She asserts that a group called the Human Rights Campaign is behind many of the efforts to shape school curricula.

The Human Rights Campaign, based in Washington, D.C., operates its “Welcoming Schools” program, through which it says it provides training and resources to create “LGBTQ and gender inclusive schools, prevent bias-based bullying, and support transgender and non-binary students.”

The HRC’s efforts include integrating school books that “reflect diversity,” and creating “inclusive spaces” within schools to allow all students to thrive “regardless of gender identity or expression.”

Planned Parenthood, meanwhile, operates a program called Get Real that is offered to school boards across the U.S. It covers topics such as anatomy, puberty, sexually transmitted diseases and “sexual identity,” the Times reported.

The U.S. has no federal standard on sex education, the newspaper added. Twenty-four states and the District of Columbia require their public schools to teach sex ed, the report said.

More information about "Sex Ed Sit Out" can be found on the event's Facebook page at https://www.facebook.com/SitOutProtest/