MILLARD, Neb. -- A mother in Millard, Neb., said she's upset by a comic book she considers sexually explicit that is in her son's elementary school library, Omaha television station KETV reported.

The comic is part of a popular series about Spider-Man and the head librarian of the Millard School District said it's been in high demand.

Physha Svendsen said the book her 6-year-old son brought home is not age-appropriate for Norris Elementary School students and wants it removed from the library.

"It has a lot of sexual undertones," she said. "They can learn this through any other place, but it's not something I allow them to learn, in my house, at least."

Svendsen said she's actively involved with her four children's education and said comic books like the one in question hold little literary value. She said she's especially concerned about her 6-year-old son, who's still developing reading skills.

Svendsen didn't elaborate on the book's literary elements that she found sexually inappropriate. Some illustrations in the book showed a female character wearing a bikini and a short skirt.

"I think having it in your school, you're still accountable for what's in there," she said.

Donna Helvering is the head librarian for the district and said each book that lands on Millard library shelves goes through a thorough selection process.

"We look at books, as far as age-appropriateness, we look at books for readability and we make sure that we're buying books that are appropriate for all our kids," Helvering said.

She said times and opinions can change, and she welcomes the complaints.

"We know that we're not always perfect and we always ask parents for their partnership and their contributions to what we purchase in our libraries," Helvering said.

She said that parents can file complaints about library books and the school is required to form a committee to evaluate the complaint within 30 days. The committee will reach a consensus about whether to keep the book on the shelves of that library.

Svendsen said she plans to hold on to the book that her son brought home while the review process takes place.