Sexus

Sexus is a biology book book found at Springfield Elementary School. It was banned by many schools, but Springfield Elementary kept it, along with Tek War, Theory of Evolution, 40 Years of Playboy, Steal This Book, Hop On Pop, and The Satanic Verses.

History
When Edna showed Principal Skinner the books they had that were banned by other schools Skinner said to her that the kids have to learn about Tek War sooner or later.