WASHINGTON — A Pentagon document classifies homosexuality as a mental disorder, decades after mental health experts abandoned that position.

The document outlines retirement or other discharge policies for service members with physical disabilities, and in a section on defects lists homosexuality alongside mental retardation and personality disorders.

Critics said the reference underscores the Pentagon’s failing policies on gays, and adds to a culture that has created uncertainty and insecurity around the treatment of homosexual service members, leading to anti-gay harassment.

Pentagon spokesman Lt. Col. Jeremy M. Martin said the policy document is under review. The Pentagon has a “don’t ask, don’t tell” policy that prohibits the military from inquiring about the sex lives of service members but requires discharges of those who openly acknowledge being gay.

The Center for the Study of Sexual Minorities in the Military, at the University of California at Santa Barbara, uncovered the document and pointed to it as further proof that the military deserves failing grades for its treatment of gays.

Nathaniel Frank, senior research fellow at the center, said, “The policy reflects the department’s continued misunderstanding of homosexuality and makes it more difficult for gays and lesbians to access mental health services.”

The document, called a Defense Department Instruction, was condemned by medical professionals, members of Congress and other experts, including the American Psychiatric Association. “It is disappointing that certain Department of Defense instructions include homosexuality as a ‘mental disorder’ more than 30 years after the mental health community recognized that such a classification was a mistake,” said Rep. Marty Meehan, D-Mass.

Congress members noted that other Pentagon regulations dealing with mental health do not include homosexuality on any lists of psychological disorders. And in a letter to Defense Secretary Donald H. Rumsfeld on Monday, nine lawmakers asked for a full review of all documents and policies to ensure they reflect that same standard.

“Based on scientific and medical evidence the APA declassified homosexuality as a mental disorder in 1973 – a position shared by all other major health and mental health organizations based on their own review of the science,” James H. Scully Jr., head of the psychiatric association, said in a letter to the Defense Department’s top doctor earlier this month.

There were 726 military members discharged under the “don’t ask, don’t tell” policy during the budget year that ended last Sept. 30. That marked the first year since 2001 that the total had increased. The number of discharges had declined each year since it peaked at 1,227 in 2001, and had fallen to 653 in 2004.