We may be a nation based on free speech, but that doesn't stop people from objecting to certain books and attempting to get them banned--so you and your children can't read them.

Each year the American Library Association releases a list of the top 10 books that generated the most controversy, naming them the most "challenged" books in public schools and libraries.

A challenge is defined as "a formal, written complaint filed with a library or school requesting that a book or other material be restricted or removed because of its content or appropriateness."

To no one's surprise, "Fifty Shades of Grey," the multimillion-selling erotic trilogy by E.L. James is on the list--but only at No. 4.

The most challenged book is "Captain Underpants," a children's story rife with bathroom humor and an irreverent attitude. Written by Dav Pilkey, the series was ripped for its offensive language. Never mind that it's getting boys to read.

"It's pretty exciting to be on a list that frequently features Mark Twain, Harper Lee and Maya Angelou," Pilkey said in a statement. "But I worry that some parents might see this list and discourage their kids from reading 'Captain Underpants,' even though they have not had a chance to read the books themselves."

The top 10 most frequently challenged books of 2012 and the reasons given for challenging the book:

1. "Captain Underpants" (series), by Dav Pilkey
Reasons: Offensive language, unsuited for age group

2. "The Absolutely True Diary of a Part-Time Indian," by Sherman Alexie
Reasons: Offensive language, racism, sexually explicit, unsuited for age group

3. "Thirteen Reasons Why," by Jay Asher
Reasons: Drugs/alcohol/smoking, sexually explicit, suicide, unsuited for age group

4. "Fifty Shades of Grey," by E. L. James
Reasons: Offensive language, sexually explicit

5. "And Tango Makes Three," by Peter Parnell and Justin Richardson
Reasons: Homosexuality, unsuited for age group

6. "The Kite Runner," by Khaled Hosseini
Reasons: Homosexuality, offensive language, religious viewpoint, sexually explicit

7. "Looking for Alaska," by John Green
Reasons: Offensive language, sexually explicit, unsuited for age group

8. "Scary Stories" (series), by Alvin Schwartz
Reasons: Unsuited for age group, violence

9. "The Glass Castle," by Jeanette Walls
Reasons: Offensive language, sexually explicit

10. "Beloved," by Toni Morrison
Reasons: Sexually explicit, religious viewpoint, violence

J.K. Rowling's "Harry Potter" books, Stephenie Meyer's "Twilight" series and Suzanne Collins' "Hunger Games" trilogy have all been on previous years' ALA lists of challenged books.

While banning or censoring books has been debated for years, another Harris Poll of 2,379 adults shows that a majority of Americans think no books should ever be banned (56 percent), while fewer than one in five say there are some books that should be banned (18 percent) and 26 percent are not sure.

The American Library Association reports that in 2012, there were 464 reports of efforts to remove books from America's library shelves, up a stunning 42 percent from the 326 challenges made in 2011. The ALA believes the majority of challenges go unreported.

--From the Editors at Netscape