PITTSBURGH — A gay Western Pennsylvania man claims co-workers who nicknamed him "Princess" and otherwise harassed him about his effeminate behavior discriminated against his gender, not his sexual orientation, and wants a federal appeals court to reinstate his related lawsuit.

But a lawyer for the defendant company said Brian Prowel's suit was rightfully dismissed by a judge last year because it is really about sexual orientation bias, which isn't under federal Title VII.

"Despite the socially controversial subject matter, this is a statutory interpretation case," defense attorney Kurt Miller argued before a three-judge panel of the 3rd U.S. Circuit Court of Appeals on Wednesday.

Prowel's lawyers contend the rampant harassment, which the company acknowledges, was at least partially fueled by Prowel's nonconformity with traditional male stereotypes.

Since 1989, the U.S. Supreme Court has held that gender stereotyping constitutes illegal gender discrimination.

Prowel, 39, of Penn Hills was fired in 2004 from his job at Wise Business Forms of Butler, where he had worked since 1991. He said the harassment occurred after he was "outed" by other employees sometime before 1997.

Prowel contends he was fired after complaining that co-workers nicknamed him "Rosebud" and "Princess" and ridiculed the way he walked, spoke and even sat.

The company said Prowel was laid off with other workers because of a business slowdown and because he developed attitude problems.

Some of the harassment was spurred by his outwardly effeminate mannerisms, which constitutes gender discrimination, Prowel's attorneys said.

They want a jury to decide whether Prowel's tormentors were targeting his sexual orientation or his failure to live up to the male stereotype.

Attorneys representing 21 women's groups have filed a friend-of-the-court brief saying Prowel's experience is the same as a woman being discriminated against for being too masculine or assertive.

But defense lawyer Miller agreed with U.S. District Judge Terry McVerry, whose 15-page opinion rejecting Prowel's initial lawsuit said Congress did not outlaw bias against sexual orientation in Title VII.

"Permitting a plaintiff to simply relabel a sexual orientation claim as one for failure to conform to gender stereotypes would evade the statutory intent of Congress," McVerry wrote.