Their favorables and unfavorables in Wednesday's poll are nearly identical, a change from the previous poll, which had Brown in a better position than Warren by this metric. The new poll shows both candidates at 49 percent favorability and Brown's unfavorables at 38 percent, Warren's at 39 percent. There is a substantial gender gap. Brown has a slight edge among male voters, 48 percent to Warren's 46 percent. But Warren gets 54 percent support among women voters to Brown's 40 percent. A recent Warren ad noted that Brown could tip the balance to a GOP-controlled Senate, which could confirm a Supreme Court Justice who would vote to overturn Roe v. Wade. President Obama has a significant lead over Mitt Romney, the state's former governor, in the White House race: 56 percent support the president, while just 36 percent support Romney. Those are tough numbers for Brown to overcome. Brown and Warren will face off for a final debate on October 30. The WBUR-FM poll surveyed 516 likely voters and was conducted October 21-22. The margin of error is plus-or-minus 4.3 percentage points.