A constant in history since the invention of the printing press is that censorship is always a threat to publishers and authors. In more recent times, the fear of U.S. parents that children might be exposed to written descriptions of or allusions to sex (or, in some parts of the U.S., magic) has caused a predictable stream of complaints and bans on certain books.

The American Library Association (ALA) tracks such bans, and this week has issued its report on the state of America’s libraries in 2013. Though the sudden popularity of E. L. James’ Fifty Shades of Grey novels might first come to mind when guessing which books have endured the most complaints in the past year, it turns out that parents across the U.S. are more concerned about a kid in his underpants.

The Adventures of Captain Underpants, the series of books that irreverently follows a superhero in ‘tighty whities’, were the most-challenged books of 2012. The Fifty Shades novels came in fourth place on the list.

In second and third place on the list were Sherman Alexie’s The Absolutely True Diary of a Part-Time Indian and Jay Asher’s Thirteen Reasons Why. Alexie’s novel is a semi-autobiographical young adult novel about his difficulties growing up poor on a U.S. Indian reservation. The book includes adult topics, such as racism, his father’s alcoholism, and multiple instances of violence. After the book began eliciting complaints from parents, Alexie wrote in the Wall Street Journal why he believes those types of complaints are meaningless when it comes to protecting children:

Of course, all during my childhood, would-be saviors tried to rescue my fellow tribal members. They wanted to rescue me. But, even then, I could only laugh at their platitudes. In those days, the cultural conservatives thought that KISS and Black Sabbath were going to impede my moral development. They wanted to protect me from sex when I had already been raped. They wanted to protect me from evil though a future serial killer had already abused me. They wanted me to profess my love for God without considering that I was the child and grandchild of men and women who’d been sexually and physically abused by generations of clergy.

Below are the ALA’s top 10 most-challenged books of 2012:

1. Captain Underpants (series) by Dav Pilkey
2. The Absolutely True Diary of a Part-Time Indian by Sherman Alexie
3. Thirteen Reasons Why by Jay Asher
4. Fifty Shades of Grey by E. L. James
5. And Tango Makes Three by Peter Parnell and Justin Richardson
6. The Kite Runner by Khaled Hosseini
7. Looking for Alaska by John Green
8. Scary Stories (series) by Alvin Schwartz
9. The Glass Castle by Jeanette Walls
10. Beloved by Toni Morrison