There should be no sexually explicit material in any instructional setting outside of a health class.  If diversity is the goal, if we want LGBTQ students to read books in English class that have characters they can relate to it doesn't have to be smut. Period.  Was Tom Sawyer about a boy and his sex life?  No. There is no need for any sexually explicit materials to ever be in a classroom.  A quick rule of thumb would be if you would arrest a 40 year old man handing said sexually explicit material to minor children on a street corner then how on Earth do we justify a 40 year man handing this material to minor children just because they work for the government?  There is no end to educational materials that are not just pornography.  Use those.