( CNN ) -- Now is not the time to repeal the military 's `` do n't ask , do n't tell '' policy on gay men and lesbians serving openly in the U.S. armed forces , Sen. John McCain said at a hearing Thursday . `` At this time , we should be inherently cautious about making any changes that would affect our military , and what changes we do make should be the product of careful and deliberate consideration , '' the Arizona Republican said at the Senate Armed Services Committee hearing . His position is not that the law should never be changed , he said , but that `` it may be premature to make such a change at this time and in this manner . '' In contrast , Defense Secretary Robert Gates urged that the repeal be signed into law as soon as possible , to avoid the issue being taken up again by the judiciary , where a repeal of the ban could be ordered immediately , rather than on the military 's timetable . A judicial fiat would be `` hazardous , '' he added . `` This can be done , and should be done , '' Gates said of the policy change . McCain questioned the results of a report that found that most military personnel would not change their career plans if the policy was changed , saying that only a fraction of military personnel responded . He also noted that the survey found opposition to the change is much higher in Army and Marine combat units than elsewhere in the military . The chairman of the Joint Chiefs of Staff , Adm. Mike Mullen , said he believes that even among those combat forces , a transition to a new law is possible . `` Should repeal occur , some soldiers and Marines may want separate shower facilities . Some may ask for different berthing . Some may even quit the service . We 'll deal with that . But I believe , and history tells , that most of them will put aside personal proclivities for something larger than themselves and for each other , '' he said . In a tense exchange between Gates and McCain , the defense secretary reiterated Mullen 's point . `` Most of the Marines who are in combat are 18 to 24 [ or ] 25 years old . Most of the them have never served with women , either . So they have had a very focused , very limited experience in the military and it 's been a tough one , '' Gates said . `` But I think that with time and adequate preparation we can mitigate their concerns . '' McCain responded , `` Well , I could n't disagree more . We send these young people into combat . We think they are mature enough to fight and die . I think they are mature enough to make a judgment on who they want to serve with and the impact on their battle effectiveness . '' McCain was upset that the military survey did not ask explicitly whether troops were in favor or against repealing `` do n't ask , do n't tell . '' The questions asked how military units would respond and adapt if it were repealed . Gates and Mullen argued that asking troops for their opinions on the repeal would be akin to a referendum on the policy , something that Mullen called a `` bad precedent . '' The argument did not sway McCain . He said that any good leader should get opinions from his subordinates before making a decision . `` I 'm almost incredulous to see that on an issue of this magnitude , we would n't at least solicit the views of the military about whether this law would be changed or not , '' he said . Mullen responded that the survey that was done gave an adequate amount of opinion , even if the question was not directly asked . `` We 've gotten in great parts their views as a result of this survey , '' Mullen said . On Friday , the committee will hear from the top brass of the Army , Navy , Air Force and Marines . While a Pew survey showed that 58 percent of the public support repealing the ban , the heads of the four military branches have either directly opposed or been unenthusiastic about the policy change , at least until the Pentagon report was finished and released . Marine Commandant James Amos has said that he opposes the change while the United States is fighting in Afghanistan because of its potential negative effect on unit cohesion . He will be joined on the second day of hearings by another Marine , the vice chairman of the Joint Chiefs , Marine Corps Gen. James Cartwright . Once the Armed Services Committee 's hearings are over , the spotlight will turn to Senate Majority Leader Harry Reid , D-Nevada . He will decide how the issue will move forward : whether to keep it as part of the Defense Authorization Bill or strip it off for a separate vote . With just weeks left for this Congress , the calendar could be the biggest factor weighing on whether the law is repealed or upheld . The House has already passed the repeal .
NEW : Troops ' opinions on policy should have been solicited , Senator John McCain says . Defense Secretary Robert Gates : Change should come from Congress , not the military . Joint Chiefs chairman : We will deal with whatever damage results from the decision .