The top reason for challenging materials is sexuality. If you combine sexism, sexually explicit material, sex education, nudity, and homosexuality, it accounts for 46% of all challenges over the 20 year period from 1990-2009. And to top it off, most of these challenges (70%) are made in schools and school libraries, institutions that are supposed to teach our children about the wide scope of topics that they will encounter in life as they grow older.
What this says to me is that parents and schools have two very different agendas. Schools, as I previously stated, are there to help children learn, which means exposing them to a plethora of ideas, topics, issues, and situations through literature, personal and historical accounts, and through the research of academics and teachers. The role of parents is to provide a moral compass and a worldview through which children can encounter the things they will learn in school. No teacher or school can teach all children according to all religious upbringings, or according to all different parental views on sex.
And so, parents, please remember that schools are not trying recruit your children into lives of sexual promiscuity, or pushing a homosexual agenda, or whatever else you might believe. They are providing examples of all the different and numerous ways in which sexuality can be lived and experienced. And this is the same with books in general. Don't get mad at the author for writing a book that speaks to people. If you don't want your child reading "filth and depravity" as you might put it, then look at what they are reading first! Or go to the library with your children. Teach them how to look at things critically and with a good moral compass and you don't need to worry that they will get sucked into a life of debauchery because they were asked to read A Brave New World or that they will become racists because of Huckleberry Finn.
Please remember that many of these books are provocative and sexual for a reason: to teach about sex! They are not giving examples of how to have sex (unless they are erotic novels or sex-ed materials), but are giving examples of the ways in which sex works in the lives of teenagers. Usually there is a lesson in there (again, except for erotic novels.)
Perhaps I have ranted too much, or perhaps I have overstepped my bounds seeing as I'm not a parent. But I know many parents and many children, and I work with young adult literature and see the ways that youth and teens react to and gain knowledge from these books. Keep this in mind if your child brings home a book you don't approve of. Review it. Talk to your child about why you think it's not a particularly positive influence. But don't--DON'T--go to the school or the school library and try to take that book from the hands of every other child there!
Thanks for listening.