WASHINGTON  A comprehensive new study on foreign militaries that have made transitions to allowing openly gay service members concludes that a speedy implementation of the change is not disruptive. The finding is in direct opposition to the stated views of Pentagon leaders, who say repealing a ban on openly gay men and women in the United States armed forces should take a year or more.

The study, “Gays in Foreign Militaries 2010: A Global Primer,” is to be released Tuesday by the Palm Center, a research group at the University of California, Santa Barbara.

The Palm Center has no official position on “don’t ask, don’t tell,” the American law that bans openly gay service members, but the group has become a leading force among advocates for repeal. The principal author of the study is Nathaniel Frank, who also wrote the book “Unfriendly Fire: How the Gay Ban Undermines the Military and Weakens America.”

The 151-page study, which updates existing studies on gay service members in Britain, Canada, Australia, South Africa and other countries, offers the first broad look at the issue in foreign militaries since Defense Secretary Robert M. Gates and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, called for an end to “don’t ask, don’t tell” earlier this month.