Maxwell Zachs is on a global crusade to normalize what until now has been considered a mental illness -- being transgender.
Zachs, 25, was born female, but three years ago he transitioned to male. In 2009, he began taking the hormone testosterone and in 2010, he went to Thailand for a double mastectomy and male chest contouring.
"There is nothing wrong with me. I am perfectly healthy, I just happen to be transgender," the Londoner told ABCNews.com in an email.
Now, he has filed a petition with change.org demanding that the World Health Organization (WHO) eliminate the diagnosis "transsexualism" from the mental disorders section of the International Classification of Diseases (ICD). He says the designation only contributes to discrimination.
"I'm a person like everybody else and I have the right to live my life without stigma, without people telling me I am sick because of how I live or how I look," he says in his petition, which has been signed by 42,000 people. "Gender is not an illness, it's just part of who I am, like being Jewish or vegetarian or sometimes talking too much!"
Zach's position is controversial. When being transgender is no longer considered a medical condition, will insurance companies in the United States refuse to pay for medical treatments -- counseling, hormone treatment and sometimes surgery -- for those whose gender identity doesn't match their DNA?
The ICD is the listing of medical conditions used by the 194 countries which are part of the World Health Assembly, the governing body of the WHO. It is used as a standard diagnostic tool for epidemiology, health management and clinical purposes worldwide.
The current edition, ICD-10, was endorsed in 1990 and is being revised. The ICD-11 is expected to be complete by 2015.
The WHO has five classifications for gender identity disorders in adults and in children, including transsexualism.
According to the ICD-10, transsexualism is defined as "a desire to live and be accepted as a member of the opposite sex, usually accompanied by the wish to make one's body as congruent as possible with one's preferred sex through surgery and hormonal treatment; presence of the transsexual identity for at least two years persistently; and not a symptom of another mental disorder, such as schizophrenia, or associated with chromosome abnormality."
Zachs, who has college degrees in English literature, indigenous studies and constitutional law, is a rabbinical student at a progressive yeshiva in Sweden, wants the classification "transsexualism" to go the same route as "homosexuality," which was discarded as a mental disorder by WHO in 1990, when the ICD-9 was revised.
But, Gregory Hartl, a spokesman for the WHO, said that Zach's petition should be directed at the international "expert group" that is charged with updating the ICD-10. Ultimately, they will make recommendations to the World Health Assembly and its member nations will vote on changes.
Two years ago, the WHO secretariat, its administrative body, recommended the ICD-10 be "updated," according to Hartl. Now, an external expert group, comprising medical professionals from member nations, is debating the matter.
"A lot of things have happened in the last 25 years," said Hartl. "And one of the things has been a lot of social and cultural changes and the acceptance of homosexuality and transgenderism."
In the United States, "homosexuality" was dropped from the American Psychiatric Association's Diagnostics and Standards Manual of Mental Disorders in 1973.
The American Psychiatric Association classifies transgenderism as a gender identity disorder. But it's now considering changing that to gender disphoria, according to New York psychiatrist Jack Drescher, who sits on the ICD-11 working group that is evaluating gender identity disorders.
But removing the classification from the ICD could be problematic.
"If they're not 'mentally disordered' than they are 'normal,'" said Drescher.
And transgender Americans see that as a double-edged sword.