A month after Florida passed legislation that prohibits classroom discussion or instruction about sexual orientation and gender identity, which the Republican governor, Ron DeSantis, signed into law in March, the volume of tweets falsely linking gay and transgender individuals to pedophilia soared, for example.

Language claiming that gay people and transgender people were “grooming” children for abuse increased 406 percent on Twitter in April, according to a study by the Human Rights Campaign and the Center for Countering Digital Hate.

The narrative was spread most widely by 10 far-right figures, including midterm candidates such as Representatives Lauren Boebert of Colorado and Marjorie Taylor Greene of Georgia, according to the report. Their tweets on “grooming” misinformation were viewed an estimated 48 million times, the report said.

In May, Ms. Boebert tweeted: “A North Carolina preschool is using LGBT flag flashcards with a pregnant man to teach kids colors. We went from Reading Rainbow to Randy Rainbow in a few decades, but don’t dare say the Left is grooming our kids!” The tweet was shared nearly 2,000 times and liked nearly 10,000 times.

Ms. Boebert and Ms. Taylor Greene did not respond to requests for comment.

On Facebook and Instagram, 59 ads also promoted the narrative that the L.G.B.T.Q.+ community and allies were “grooming” children, the report found. Meta, the owner of Facebook and Instagram, accepted up to $24,987 for the ads, which were served to users over 2.1 million times, according to the report.

Meta said it had removed several of the ads mentioned in the report.

“The repeated pushing of ‘groomer’ narratives has resulted in a wider anti-L.G.B.T. moral panic that has been influencing state and federal legislation and is likely to be a significant midterm issue,” said David Thiel, the chief technical officer at the Stanford Internet Observatory, which studies online extremism and disinformation.