A test case to determine whether a convicted criminal in Boston should be granted a $20,000 (£10,000) sex-change operation at prison expense is still on-going after a year, despite costing $52,000 in expert witness fees alone.

The crux of the case rests on whether Michelle Kosilek, formerly Robert Kosilek, needs the surgery as a matter of medical necessity.

Kosilek, 58, was convicted of murdering his wife in 1990, claiming it was in self-defence after she split burning tea on his genitals.

In 1993 he changed his name to Michelle and in 2002, after being diagnosed with gender identity disorder, a judge ruled that medical treatment, including hormone treatment, laser hair removal and psychotherapy was appropriate.

Despite previous legal challenges however, no inmate has yet to receive a full sex-change.

Lawyers for Kosilek claim that the operation is essential for their client’s well-being in the same way as a procedure like heart surgery, and that refusal violates his 8th Amendment protection against cruel and unusual punishment.

Kosilek has been diagnosed with depression and twice attempted suicide while in prison.

Two doctors, paid for by the Correction Department’s outside health care provider, and two psychiatrists, provided free by a Boston Law-firm, support their claim by recommending surgery .

But a further two correction experts, employed directly by the Correction Department, refute it, citing that Kosilek’s depression has lessened since the start of hormone treatment, something Kosilek strongly denies.

Former Commissioner Kathleen Dennehy has also weighed in, stating that the operation would present security risks whether Kosilek was held in a male or female prison.

The outcome of the case is hotly anticipated.

Republican state Senator Scott Brown, has already unsuccessfully tried to introduce a bill banning sex-change surgery for prisoners.

“They are there because they’ve broken the law,” he said.

“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.”

In Winsconsin, five inmate are suing the Department of Corrections after similar Legislature was passed refusing them hormone treatment or sex-change surgery.

Across the state meanwhile, a further ten inmates are diagnosed with gender identity disorder and at least two have asked for sex-change surgery.