CHICAGO (AP) -- The American Medical Association on Tuesday voted to oppose the military's 'don't ask, don't tell' policy, and declared that gay marriage bans contribute to health disparities.

The nation's largest doctors' group stopped short of saying it would seek to overturn marriage bans, but its new stance angered conservative activists and provides a fresh boost to lobbying efforts by gay-rights advocates.

"It's highly significant that the AMA as one of this country's leading professional associations has taken a position on both of these issues," said Rea Carey, executive director of the National Gay and Lesbian Task Force, a Washington-based advocacy group.

The health disparities measure "in the long run, will certainly help efforts to win marriage equality," Carey said.

Whether the AMA's lobbying power will hasten efforts to overturn the 'don't ask, don't tell' law remains to be seen. President Barack Obama has said he is working with congressional leaders to end the policy, and the AMA's stance will likely help, although gay rights issues have been upstaged by Obama's health care overhaul battle.

The AMA's vote took place at the group's interim policy-making meeting in Houston, a day after AMA delegates voted to affirm their support for health reform.

The health disparities policy is based on evidence showing that married couples are more likely to have health insurance, and that the uninsured have a high risk for "living sicker and dying younger," said Dr. Peter Carmel, an AMA board member.

Same-sex families lack other benefits afforded married couples, including tax breaks, spouse benefits under retirement plans and Social Security survivor benefits -- all of which can put their health at risk, according to an AMA council report presented at the meeting.

But Jenny Tyree, a marriage analyst for Focus on the Family Action, a conservative advocacy group, called it a health insurance problem, not a marriage problem. "We all know there are problems with health care so let's solve the problem of the uninsured, rather than messing with marriage," she said.

Doctors who pushed the group to oppose 'don't ask, don't tell' say the policy forcing gay service members to keep their sexual orientation secret has "a chilling effect" on open communication between gays and their doctors.

"A law which makes people lie to their physicians is a bad law," said Dr. David Fassler, a University of Vermont psychiatry professor who attended the meeting.

In other action Tuesday, the AMA moved closer to supporting medical marijuana, adopting a measure urging a federal review of marijuana's status as a controlled substance. That would make it easier to do research, which the AMA said could lead to development of marijuana-based medications that don't require smoking. The group said its position doesn't mean it supports legalizing marijuana.

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