Army Chief of Staff Gen. George W. Casey says he sees anxiety in the armed forces over how possible changes in the law that bans openly gay servicemen and women would be implemented.

During a visit to Fort Carson, Colo., on Thursday, Casey said it's important to give everyone in the armed forces an opportunity to be heard on the issue without being penalized.

President Barack Obama wants to change the 1993 law known as "don't ask, don't tell," saying it unfairly punishes people who want to serve.

Defense Secretary Robert Gates has ordered a comprehensive study on how to lift the ban without hurting the forces.

In testimony before Congress last week, Casey and Air Force Chief of Staff Gen. Norton Schwartz said they had serious concerns about eliminating the ban with two wars raging.