A woman's sex change operation does not free her ex-husband from his alimony obligation, a judge said Wednesday.

Attorneys for Lawrence Roach, 48, had argued his 55-year-old ex-wife's decision to switch genders and change her name from Julia to Julio Roberto Silverwolf voided their 2004 divorce agreement.

''It's illegal for a man to marry a man and it should likewise be illegal for a man to pay alimony to a man,'' said John McGuire, one of Roach's attorneys.

Circuit Judge Jack R. St. Arnold, however, ruled that in the eyes of the law, nothing changed significantly enough to free Roach from his $1,250-a-month obligation.

The judge said since Florida courts have ruled sex-change surgery cannot legally change a person's birth gender, Roach technically is not paying alimony to a man.

Gender definitions are ''a question that raises issues of public policy that should be addressed by the Legislature, not the Florida courts,'' St. Arnold wrote.

Silverwolf's lawyer, Gregory Nevins, said the language of the divorce decree is clear - Roach agreed to pay alimony until his ex-wife dies or remarries.

Nevins said he and his client were pleased with the ruling although they disagree with Florida's refusal to legally recognize gender reassignment surgery.

Roach, a utility worker who has since remarried, said he will press his fight to end the payments.

''We're going to try everything we can,'' he said. ''I can't rest until I get satisfaction.''

The case is the second transsexual rights showdown in Pinellas County in less than a week. On Friday, city commissioners voted 5-2 to fire Largo's city manager, Steve Stanton, after he announced he was a transsexual.

An Ohio appeals court ruled in September 2004 that a Montgomery County man must continue to pay alimony to his transsexual ex-wife because her sex change wasn't reason enough to violate the agreement.