Editor's note: This is part of a series of reports CNN.com is featuring from an upcoming, six-hour television event, "God's Warriors," hosted by CNN chief international correspondent Christiane Amanpour.
Gehad al-Khalek of Egypt says the hijab is a focus on inner beauty.
(CNN) -- Last year at Christmastime, Rehan Seyam, a Muslim living in New Jersey, went to pick up some things at a local Wal-Mart. Seeing her distinctive traditional Muslim head covering called a "hijab," a man in the store, addressing her directly, sang "The 12 Days of Christmas" using insulting lyrics about terrorism and Osama bin Laden.
She was stunned.
"Do I look like a terrorist to you?" Seyam said she asked the man.
According to Seyam, the man replied, "What else does a terrorist look like?"
Such stories are not altogether uncommon for Muslim Americans. According to a recent poll by the Pew Research Center, 53 percent of Muslims living in America said it has become more difficult to be a Muslim in the United States since the September 11, 2001, terrorist attacks. Fifty-one percent said they are "very worried" or "somewhat worried" that women wearing the hijab are treated poorly, according to the poll.
A simple headscarf generally used by women to hide the hair from view, the hijab has become so controversial among some that several countries have banned or considered banning Muslim women from wearing them in public places. In light of this contentiousness, why do Muslim women choose to wear the hijab? Watch the making of CNN's TV special "God's Warriors" »
Gehad al-Khalek lives in Egypt and says the hijab is a focus on inner beauty.
"I want to shift the attention from my outer self to my inner self when I deal with someone, I don't want them to look at me in a way that wouldn't suit me," she told CNN in an upcoming documentary called "God's Warriors."
Al-Khalek is fluent in English and German; studied in Europe; plays Western music on her guitar; and spent time working for a women's rights organization.
She wears the hijab -- and says it's not just for religious reasons.
"My own conclusion was it is debatable whether it is a religious obligation or not, but I chose to keep it on because I do believe in modesty and you shouldn't be showing off yourself," al-Khalek said.
The Quran calls for women to be modest in their dress but interpretation of the edict varies widely, according to religious experts who spoke with CNN. An author who has written widely on Islam told CNN the Quran does not require women to wear the hijab.
"There's nothing in the Quran about all women having to be veiled or secluded in a certain part of the house. That came in later [after Prophet Mohammed's time]," said religious historian and author Karen Armstrong.
For Seyam, the hijab is a religious duty. "It's God's wish," she said.
"It's a requirement by God. He wants us to cover. He wants us to be modest," Seyam said.
But as important as the hijab is to her, Seyam's decision to cover her hair wasn't one she made easily.
"It was very dramatic for me. And I remember, even now thinking about it, it really does make my heart beat a little bit faster," she said, "I was making a decision I knew was permanent. You put on hijab, you don't take it off."
Through her childhood growing up in Long Island, New York, Seyam prayed with her devout Muslim parents, but says she was just "going through the motions." It wasn't until college that she decided to wear a hijab consistently.
Influenced by her more devout friends, Seyam decided being a good Muslim meant covering her head.
"My sole purpose is to be here for the sake of Allah, and I'm doing something that he specifically says that you should be doing."
Seyam said there were practical factors in her decision as well. "I'm sick of guys catcalling. It was just driving me crazy. I felt like a piece of meat."
But Seyam says she traded in catcalling for a different kind of negative attention. People "look at me as if I am threatening and I do not feel like I am threatening looking. I don't feel I should instill fear in anybody's heart, but I do feel like I get dirty looks," she said.
Still, Seyam says her faith sustains her and that wearing the hijab is an important part of that faith.
"I'm not here to live my life and do whatever I want. I'm here to worship God," Seyam said. "I don't think that everybody has that, and I think that I'm lucky for it." E-mail to a friend