This proposal will be used to ban books with even a hint of LGBT themes, which can have devastating effects.

1. LGBT people exist everywhere. There is ZERO threat involved in children knowing that they exist. In fact, exposure to LGBT people may reduce risk of severe bullying and harassment that (according to the CDC https://www.cdc.gov/lgbthealth/youth.htm) 34% of LGBT students face on school property. 
2. LGBT people are in schools. They are students, teachers, parents, cafeteria staff, office staff, and janitors. Deciding that these people (ANY group of people, even) are forbidden from discussion is not only ludicrous and impossible but also, isolating and humiliating. 
3. MANY studies have demonstrated that a safe and welcoming environment is necessary to prevent LGBT youth suicide. I beg you, for the sake of your children's lives. If you won't support them at home (as only 37% of families will provide a supportive home environment https://www.thetrevorproject.org/resources/article/facts-about-lgbtq-youth-suicide/), school may be their only chance. The Trevor Project is an organization that collects such facts and supports youth at risk of suicide. You can learn more and find sources here: https://www.thetrevorproject.org/research-briefs/lgbtq-gender-affirming-spaces/ see also: https://www.thetrevorproject.org/resources/article/facts-about-lgbtq-youth-suicide/ 
4. I would argue that no parent actually has the "right" to pretend that 7.1% of the American population (Gallup: https://news.gallup.com/poll/332522/percentage-americans-lgbt.aspx) doesn't exist or to erase their existence. School is for teaching facts to prepare students for the big broad world out there, not conservative fantasies where inconvenient minorities just disappear.