PHILADELPHIA — A federal appeals court must decide whether a Pennsylvania middle school can suspend a student who, at home on her own time, created a lewd MySpace page aimed at her principal.

The Web page, which used a fake name but an actual photo of the principal, was purported to have been posted by a 40-year-old Alabama school principal who described himself, through a string of sexual vulgarities, as a pedophile and sex addict. The Internet address included the phrase "children rock my bed."

The case, argued in the 3rd U.S. Circuit Court of Appeals on Tuesday, raises broad issues about the limits of school discipline for off-campus behavior that affects the atmosphere at school. A rash of similar cases have surfaced across the country, with mixed rulings, but none has reached the U.S. Supreme Court.

The American Civil Liberties Union argues that students enjoy free-speech rights off-campus that protect such parodies, however vulgar.

"Parents give up some control at the schoolhouse gate," Mary Catherine Roper, an ACLU lawyer in Pennsylvania, told the appeals court judges. "When the students walk back out, they again are under control of their parents."

However, a lawyer for the Blue Mountain School District in Schuylkill County said the eighth grader's actions in March 2007 caused a disturbance that reverberated inside school and harmed the principal. Students were buzzing about the site for several days, and school administrators quickly became aware of it.

"Quite frankly, this could have affected his career," school board lawyer Jon Riba argued. "At the very least, it creates an impression that this man is unstable."

Roper called the site clearly satiric — and juvenile.

The Supreme Court has said that students enjoy some free-speech rights, such as the right to wear black armbands to protest the Vietnam War, while rejecting the right to lace a school speech with sexual innuendo.