The study -- conducted by the Palm Center at UCLA by a panel that included faculty members from the U.S. Military Academy, Air Force Academy, Naval Academy and Marine Corps War College -- concluded the policy change had no negative impact on readiness, cohesion, recruitment and retention, or assaults and harassment. It did find what it called "individual variations" but no net negative impact on morale.
"Our conclusion, based on all of the evidence available to us, is that DADT repeal has had no overall negative impact on military readiness or its component dimensions, including cohesion, recruitment, retention, assaults, harassment or morale," the report concluded. "Although we identified a few downsides that followed from the policy change, we identified upsides as well, and in no case did negative consequences outweigh benefits. If anything, DADT repeal appears to have enhanced the military's ability to pursue its mission."
While some gay and lesbian service members report incidents of name-calling and harassment in the past year, the general counsel to the Defense Department says that was to be expected.
"We were not fooling ourselves into believing there would be no incidents," Jeh C. Johnson told The New York Times.
Officials say about 2 percent of the military is gay, lesbian or bisexual. OutServe, an advocacy group, said almost one-third of the open gays have come out in the past year.
Signs of the change include an informal group of homosexual service members at the Pentagon that meets for coffee twice a week in a Dunkin' Donuts in the food court there. The group was started quietly in 2005 by a few Air Force officers and now had as many as 40 people attending its gatherings.
President Barack Obama said it was a testament to the military's professionalism that the change was implemented in an orderly fashion that preserved "unit cohesion, recruitment, retention and military effectiveness."
"As commander in chief, I've seen that our national security has been strengthened because we are no longer denied the skills and talents of those patriotic Americans who happen to be gay or lesbian," he said.
House Democratic Whip Steny Hoyer of Maryland said the repeal "opened doors for LGBT [lesbian, gay, bisexual and transgender] Americans wishing to join our armed forces and ended the fearful prospect of discharge for those who were already serving."
First lady Michelle Obama and several Democratic members of Congress posted comments on their Twitter pages to note the one-year anniversary, The Hill reported.
"DADT was repealed one year ago today. Our country is stronger, freer, and fairer because of it. Just one more way we're moving forward," Michelle Obama posted.
Rep. Debbie Wasserman Schultz, D-Fla., posted: "One year ago, our nation took a historic step forward and affirmed once again that we are greater together -- as we wiped #DADT off the books."
"Proud to have supported #DADT repeal," Rep. Chris Murphy, D-Conn., posted. "The brave men & women who serve are now free to be who they are & love who they like."
2014: The Year in Fashion [PHOTOS]