WASHINGTON – Defense Secretary Robert Gates on Thursday urged gay members of the military to complete a questionnaire on a potential repeal of the “don’t ask, don’t tell” policy, as a leading gay rights group warned that troops could be outed by the survey.

“I strongly encourage gays and lesbians who are in the military to fill out these forms,” Gates said. “We organized this in a way to protect their privacy and the confidentiality of their responses through a third party, and it’s important that we hear from them as well as everybody else.”

The Pentagon is studying the potential impact of repealing the ban on gay men and lesbians openly serving in uniform, and about 200,000 active-duty troops and 200,000 reserve troops were e-mailed a link to the survey.

The survey asks service members about their general experiences in the military, about experiences serving with people they think are gay and for opinions on how repealing the ban might affect retention, referrals, unit cohesion, privacy and military family life, the Pentagon said.

But the Servicemembers Legal Defense Network, a nonpartisan legal services organization providing counsel to service members discharged under the gay ban, reminded troops that the military is still enforcing the ban and said completing the survey could result in a discharge.

“While the surveys are apparently designed to protect the individual’s privacy, there is no guarantee of privacy and DOD has not agreed to provide immunity to service members whose privacy may be inadvertently violated or who inadvertently outs himself or herself,” Executive Director Aubrey Sarvis said Thursday. “If a service member still wishes to participate, he or she should only do so in a manner that does not reveal sexual orientation.”