MANSFIELD - The sex change lawsuit of a Mansfield man in prison for murdering his wife is being closely watched by advocates for inmates across the country who want to undergo a sex change.

The lawsuit by Michelle Kosilek - formerly Robert - went to trial more than a year ago and has become bogged down in U.S. District Court in Boston, where a judge has not yet ruled on the case.

There have been hundreds of hours of testimony from witnesses, including 10 medical specialists paid tens of thousands of dollars. The judge himself even hired an expert to help him make sense of it all.

The question at the center of the case: Should a murderer serving life in prison get a sex-change operation at taxpayer expense?

Transgender inmates like Kosilek in other states have sued prison officials, and not one has succeeded in persuading a judge to order a sex-change operation. The Massachusetts Correction Department is vigorously fighting Kosilek's request for surgery, saying it would create a security nightmare and make Kosilek a target for sexual assault.

An Associated Press review of the case, including figures obtained through Freedom of Information Act requests and interviews, found that the Correction Department and its outside health care provider have spent more than $52,000 on experts to testify about an operation that would cost about $20,000.

The duration and expense of the case have outraged some lawmakers who insist that taxpayers should not have to pay for inmates to have surgery that most private insurers reject as elective.

"They are prisoners. They are there because they've broken the law," said state Sen. Scott Brown, R-Wrentham, who unsuccessfully introduced a bill to ban sex-change surgery for inmates. "Other folks, people who want to get these types of surgeries, they have to go through their insurance carrier or save up for it and do it independently. Yet if you are in prison, you can do it for nothing? That doesn't make a lot of sense."

But advocates say in some cases - such as that of Kosilek, who has twice attempted suicide - sex-change surgery is as much a medical necessity as treatment for diabetes or high blood pressure.

"The duty belongs to the prison to figure out how to fulfill its constitutional obligations to both provide adequate medical care and provide a fundamental security for all inmates," said Cole Thaler, an attorney with Lambda Legal, a gay- and transgender-rights group.

Kosilek, 58, was convicted of strangling his wife in their Mansfield condominium 1990 before dumping her body in her car and leaving it at Emerald Square mall in North Attleboro.

At his trial, he was allowed to wear women's jeans and sneakers and cosmetics.

Kosilek claimed he killed his wife in self-defense after she spilled boiling tea on his genitals.

Robert Kosilek legally changed his name to Michelle in 1993, and has sued the Correction Department twice, arguing that its refusal to allow a sex-change operation violates the Eighth Amendment protection against cruel and unusual punishment. In 2002, U.S. District Judge Mark Wolf ruled that Kosilek was entitled to medical treatment for gender identity disorder, but stopped short of ordering the surgery. Kosilek sued again in 2005, arguing that the hormone treatments, laser hair removal and psychotherapy she has received since Wolf's ruling have not relieved her anxiety and depression.

"I would not want to continue existing like this," Kosilek testified.

Kosilek's second trial, which began in May 2006, has featured expert testimony from 10 doctors, psychiatrists and psychotherapists. Wolf has not indicated when he will rule.

The Correction Department has spent about $33,000 on two experts it retained to evaluate Kosilek. Both Cynthia Osborne, a Baltimore psychotherapist, and Chester Schmidt, a psychiatry professor at Johns Hopkins University, said Kosilek does not need the surgery. Schmidt's fee alone was $350 per hour.

Two other doctors retained and paid for by the department's outside health provider, the University of Massachusetts Correctional Health Program, at a cost of just under $19,000 said they believe the surgery is medically necessary for Kosilek. Two other doctors who work for the health provider agreed with that.

In addition, two psychiatrists who testified for Kosilek recommended the surgery. A Boston law firm representing Kosilek for free paid for those experts but would not disclose the cost.

In Wisconsin, five inmates sued after the Legislature passed a law that bars Correction Department funding for hormone treatments or sex-change surgery. The case is expected to go to trial in October.

Those who argue against allowing the surgery say it could open the floodgates to other inmates who want sex-change operations or other treatments considered elective.

In Massachusetts, 10 inmates have been diagnosed with gender identity disorder and are receiving hormone treatments. Two other inmates besides Kosilek have asked for sex-change surgery.

Corrections officials say their decision to deny the surgery has nothing to do with costs or the politics of crime. They cite the testimony of their experts and Kosilek himself that her feelings of depression have diminished since she began taking hormones.

Former Commissioner Kathleen Dennehy testified that allowing Kosilek to complete the transformation into a woman would present a security problem. Whether she stays in a male prison or is transferred to a female prison, she could become a target for sexual assault, Dennehy testified.

Dennehy also said prison officials cannot be influenced by Kosilek's talk of suicide.

"The department does not negotiate or respond to threats of harm or suicide in an effort to barter," she said. "You couldn't run a prison with that kind of leveraging going on."