An extensive Pentagon report about the armed forces' attitudes toward gays in the military gives a boost to the stalled push by President Barack Obama to repeal the 17-year-old 'don't ask, don't tell' law, undercutting arguments by Republicans and others that such a change would unduly strain the armed forces. After nine months of study and unprecedented polling of the nation's troops, the Pentagon concluded Tuesday that allowing gays and lesbians to serve openly posed a 'low risk' of disruption. The report found that a large majority of troops were comfortable with the prospect of overturning long-standing restrictions on gays in uniform and that they expected it would have little or no effect on their units. 'This can be done, and should be done, without posing a serious risk to military readiness,' Defense Secretary Robert Gates said. He urged the Senate to pass legislation before it adjourns this month and a new Congress - in which the GOP will hold much more sway - is seated in January. Senate Democrats are pressing to move fast and have scheduled hearings starting Thursday. Majority Leader Harry Reid, D-Nev., has vowed to hold a vote on the bill this month, but whether he'll be successful is an open question. 'The report is common sense,' Reid said Tuesday. 'It's no surprise to me. It's no surprise to the American people.' The bill's fate rests largely on the votes of about 10 moderate senators of both parties who are waiting to read the report before making their decision. Already Sens. Susan Collins, R-Maine, Richard Lugar, R-Ind., and Lisa Murkowski, R-Alaska, have said they will vote to end the ban if Democrats permit a fair debate. Sen. Ben Nelson, D-Neb., said ending the ban 'doesn't have to be done during the lame-duck session.' Obama also asked the Senate to vote soon, 'so I can sign this repeal into law this year and ensure that Americans who are willing to risk their lives for their country are treated fairly and equally.' On Thursday, the Senate Armed Services Committee will question Gates; Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff; and the report's co-authors, Army Gen. Carter Ham and Pentagon counsel Jeh Johnson. On Friday, the committee will ask the chiefs of staff of the Army, Navy and Air Force, as well as the commandants of the Coast Guard and Marine Corps, to express their personal views - which do not necessarily match up with the Obama administration's position. The panel's ranking Republican, Sen. John McCain of Arizona, is a lead critic of efforts to repeal the ban. He did not comment Tuesday on the report. Gates acknowledged Tuesday that military leaders of the individual branches of the armed services are 'less sanguine' about the need to end the ban. The joint chiefs met with Obama at the White House on Monday to discuss the report. They have also written letters to Gates expressing their views on the study's findings. Pentagon officials declined to make the letters public. Regardless of the top brass's skepticism, 'this report is going to be perhaps the most effective lobbying tool that repeal advocates will have over the next two weeks in the Senate,' said Aubrey Sarvis, executive director of the Servicemembers Legal Defense Network, a group pushing to end the ban. 'We recognize that there will be some initial resistance from some of the chiefs, but at the end of the day, they have all said that if Congress acts, they will salute and implement this change.' Military leaders have emphasized that they will obey the law, regardless if Congress changes it. But conflicts between personal beliefs and professional obligation have led to awkward moments for military leaders. Gates, who has long said that he supports Obama's desire to change the policy, shed more light on his personal opinion Tuesday. 'We spend a lot of time in the military talking about integrity and honor and values,' he said in response to reporters' questions. 'One of the things that is most important to me is personal integrity, and a policy or a law that in effect requires people to lie gives me a problem.' Legislation pending in the Senate states that the Defense Department would not have to end 'don't ask, don't tell' until it certifies to the White House that the military is ready to do so. It's unclear whether that would take months or even years; Gates and other military and defense officials dodged questions Tuesday about how long the department would need. 'The president would be watching very closely to ensure that we don't dawdle or slow roll this,' Gates said. At the same time, he said his 'greatest fear' is that federal courts might intervene and overturn the law immediately, forcing the Pentagon to adapt overnight. The 362-page report - based largely on survey responses from 115,000 members of the military - concludes that 'the risk of repeal of don't ask, don't tell to overall military effectiveness is low.' While ending the ban would probably bring about 'limited and isolated disruption' to unit cohesion and retention, 'we do not believe this disruption will be widespread or long-lasting,' it stated. The survey found that 69 percent of respondents said they had served with someone in their unit who they believed to be gay or lesbian. Of those who did, 92 percent stated that their unit's ability to work together was very good, good, or neither good nor poor, the report said. Combat units reported similar responses, with 89 percent of Army combat units and 84 percent of Marine combat units saying they had good or neutral experiences working with gays and lesbians. At the same time, the survey found that 30 percent of respondents over all - and between 40 and 60 percent of the Marine Corps - either expressed concern or predicted a negative reaction if Congress were to repeal the law. Those concerns are 'driven by misperceptions and stereotypes about what it would mean if gay service members were allowed to be 'open' about their sexual orientation,' Johnson and Ham concluded in the report. Such concerns are 'exaggerated, and not consistent with the reported experiences of many service members,' they said. About 28 percent of the 400,000 active-duty and reserve troops who received copies of the survey responded, the report said. The survey had a margin of error of plus or minus 1 percentage point. Even if the bill clears the Senate this month, it must be reconsidered by the House, which passed a similar version in May. Rep. Howard McKeon of California, the ranking Republican on the House Armed Services Committee, said Tuesday that he also wants his panel to hear from top military leaders. Scheduling conflicts are likely to prohibit the committee from holding hearings, said a spokeswoman for the panel's chairman, Rep. Ike Skelton, D-Mo. Opponents of lifting the ban said lawmakers should not vote before the end of the year. 'This entire exercise has been done to lend support to the president's political exercises,' said Elaine Donnelly, executive director of the Center for Military Readiness. Her group is preparing a report card on the report that will score its factual accuracy, whether it fairly included the viewpoints of concerned troops and how Johnson and Ham reached their conclusions. Lawmakers should take as long as necessary to review it, she said. Staff writer Ben Pershing contributed to this report. 