Look up the code F66.0 in the International Classification of Diseases (ICD), the world's most widely used diagnostic reference, and you’ll find sexual maturation disorder. That seemingly official psychological condition occurs when uncertainty about sexual orientation makes a person depressed or anxious, according to the ICD. Rooted in Freudian theory, which views homosexuality as merely an “immature” state of sexual development, a gay teenager could be labeled mentally ill under this category simply because he is grappling with conflicting or confusing sexual desires, notes Susan Cochran, an epidemiologist at the University of California, Los Angeles.

Today, it's not clear that any such linear trajectory of sexual development exists, Cochran says. After reviewing decades of psychological and epidemiological studies on sexual orientation and mental health, she and others on a panel appointed by the World Health Organization (WHO) have recommended that F66.0 and four other homosexuality-related psychological disorders be stricken from the ICD.

“It is not justifiable from a clinical, public health or research perspective for a diagnostic classification to be based on sexual orientation,” the group wrote in a report released last month. All such classifications need to be eliminated from the ICD not only because they lack scientific basis or clinical utility, but also as a "human rights issue," says Cochran, who led the working group.

The recommendations must undergo several reviews now, including a vote by ministers of health from more than 170 of the WHO countries. There is likely to be "tremendous pushback" from countries in which homosexuality is considered an illness or a crime, says epidemiologist Chris Beyrer of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. The anti-homosexuality laws recently passed in Russia, Uganda, and Nigeria and others now being debated in other countries makes this "precisely the right time for the WHO to stand up, take an evidence-based approach and say [homosexuality] is not a pathology," he says.

Every medical incident reported in the roughly 170 countries that belong to WHO gets an ICD code used for insurance billing, medical records, and epidemiological research. The WHO panel's recommendation to eliminate all sexual orientation–related disorders in the ICD echoes changes that occurred in the United States decades ago, says psychiatrist Jack Drescher of New York Medical College in Valhalla, who was also on the WHO panel. In the 1970s, there was a “big fight” within the American Psychiatric Association (APA) over whether homosexuality should be considered a mental illness, Drescher says.

Although APA removed the diagnosis from the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1973, they replaced it with a new disorder called sexual orientation disturbance as a political compromise, he says. This was later changed to ego-dystonic homosexuality. The disorder referred to the anxiety or depression one might feel about being homosexual or the desire to change one’s sexual orientation. For example, if a woman found after 10 years of marriage to a man that she was attracted to women, she could be considered mentally ill.

The condition, still listed in the ICD, was “created out of air,” Drescher says. By 1987, most clinicians who supported the diagnosis had left APA, enabling the organization to eliminate sexual orientation–related disorders altogether from the DSM, he says. Drescher, Cochran, and other scientists hope that a similar moment is coming for the ICD, which deleted homosexuality as a disorder in 1990. “It was surprising” to discover how few studies have been published on the five remaining diagnostic categories over the past 20 years, Cochran says. In addition, the diagnoses “have not generated a body of research, are not routinely reported to WHO by any Member State and are not used in WHO’s calculations of the global burden of disease,” according to the report.

Based on this evidence, the working group recommends that physicians treat anxiety or depression in gay and bisexual people as they would in anyone else. As it now stands, the diagnoses can be misused to justify "conversion" treatments considered unethical by mental health professionals and can obscure "very normal" reactions to harassment and prejudice that gays encounter on a regular basis, Cochran says.

For his own part, Drescher doesn’t have much hope the panel’s recommendations will prompt changes in countries where gays are being persecuted. Drescher helped prepare a letter explaining the scientific understanding of homosexuality to Ugandan President Yoweri Museveni before the president signed an antigay bill into law. Yet Museveni simply put together his own group of scientists “who reviewed our material and came to exactly the opposite conclusion,” Drescher says. “I don’t think [science] really matters in these witch hunts.”

After Cochran’s group drafted its recommendations, WHO appointed a second panel of reviewers, including mental health researchers and physicians from countries where homosexuality is highly stigmatized or criminalized, such as Saudi Arabia and Russia. Of this group, “none of the peer reviewers tried to make a case that these categories should be retained,” says Geoffrey Reed, senior WHO project officer for the revision of the section of ICD dealing with mental and behavioral disorders.

One presenter to the working group from Iran did claim that the sexual orientation–related diagnoses protect gays from prison or execution by providing a medical explanation for their actions, Drescher says. After consulting with organizations that track such issues worldwide, however, the group could not find a single instance in which a gay person had used such a defense.

Now that the recommendations are out, WHO will perform extensive field tests in Mexico, Brazil, India, Lebanon, South Africa, and other countries to determine if the new criteria help clinicians make more accurate diagnoses, using case examples as well as real-life health settings, Reed says. The fact that the recommendations are grounded in data “doesn’t automatically mean people will be persuaded,” he acknowledges, but “our job is to assemble the best evidence that we can.”

*Correction, 7 July, 11:11 a.m.: This article has been corrected to reflect that in 1973, APA replaced homosexuality with a new disorder called sexual orientation disturbance, which was later changed to ego-dystonic homosexuality.