As for Perry' claim that sex surgery stems violence, experts say there is no evidence that accompanying hormone therapy plays a role in diminishing aggression.
Estrogen is part of the hormone protocol recommended by the standards of care for gender reassignment surgery set by the World Professional Association for Transgender Health.
Older studies have linked the male hormone testosterone to enhanced aggression, but a more recent Penn State University study says popular misconceptions may be inaccurate.
Chemical castration, using Depo Provera to reduce libido and sexual activity, has been controversially used among sex offenders.
Jack Halberstam, who is transgender and a professor of American and gender studies at University of Southern California, said that Perry's publicized statements are "very sketchy and a desperate defense ploy."
"It harkens back to the discourse on multiple personalities a decade ago –- that another personality has taken over my body space," he said. "It's an idea that we are simply competing personalities or selves. If you talk about transgenderism or psychopathology, nobody really believes that stuff. That research is now pretty much flawed."
Halberstam said Perry had a "weak defense."
"Even if we as a person are less aggressive once we resolved a gender disorder, it does not absolve the responsibility of killing three women," he said. "As a legal defense, putting away the science, it's absolute nonsense."
He is also critical of the way in which Perry's case reinforces negative stereotypes about those who are transgender.
"The science is very shaky and the rational that why [Doug] may have committed the murders was that he envied the maternal function of the female body, seems to seal his fate. Making being transgender into a motivating factor for murder is almost like the horror film, 'Dressed to Kill.' It feeds directly into the horror stories about gender identity disorder."
Mara Keisling, executive director of the National Center for Transgender Equality, agreed.
"This doesn't seem like a transgender issue to me," she said. "The media loves this kind of case. If this were a minister, it wouldn't be framed that way. This is not about that part of [Perry's] identity, it's about being a murderer."