What began with a few metres of tartan in Missouri has sparked a debate about freedom, symbols and cultural dress in the United States.

More than 1600 people have signed an internet petition seeking an apology for the student.

"It's a kilt. It's going to turn heads, but I never believed it would have become what it is," Warmack said.

"I had a teacher say you weren't really wearing it to honour your heritage. You were wearing it for the reaction. No, I wasn't," he said.

Warmack said his interest in his family's Scottish ties was sparked by Mel Gibson's 1995 movie Braveheart, about William Wallace's battle to overthrow English rule in 13th century Scotland.

Warmack reads books about Scotland and checks websites to learn more about his family's genealogy.

Then, he bought a kilt off the internet to wear to his school's formal dance in November.

Warmack said he showed it to a vice principal before the dance, who joked he'd better wear something underneath it, and Warmack assured him he would.

His parents, Terry and Paula, helped him piece together the rest of his outfit, a white shirt and black tie with white socks and black boots.

After Nathan and his date posed for pictures, Principal Rick McClard, who had not previously seen the kilt, told the student he had to go and change. Warmack refused.

Several Scottish heritage organisations in the US are angry, pointing out that a kilt is a symbol of Scottish pride and considered formal dress." See:

http://www.smh.com.au/news/unusual-tales/scottish-pride-turns-to-dance-ban/2005/12/21/1135032024904.html