Kosilek, who was known as Robert and living in Mansfield in when he was convicted of killing his wife, Cheryl, in 1990, first sued the Massachusetts Department of Correction 12 years ago.
Wolf ruled two years later that Kosilek was entitled to treatment for gender-identity disorder, but did not order surgery. She sued again in 2005 which led to Wolf's most recent ruling in September 2012, which the state appealed, brining the case to the Federal Court of Appeals.
Sex change operations can cost up to $20,000. Many insurance companies reject the surgery as elective. Prison officials have argued that allowing Kosilek to have the surgery would make her a target for sexual assaults by other inmates.