(CNN) -- Sen. John McCain's campaign rebuked Sen. Joe Biden on Tuesday, saying the Democratic vice presidential nominee had "sunk to a new low" by raising a debate over who cares more for special needs children. Sen. Joseph Biden embraces a supporter during a campaign stop in Columbia, Missouri, on Tuesday. The Republican camp's sharp response came after Biden said GOP advocates for children with birth defects should support stem cell research. During a campaign event in Columbia, Missouri, Biden did not mention his Republican counterpart by name but said, "I hear all this talk about how the Republicans are going to work in dealing with parents who have both the joy ... and the difficulty of raising a child who has a developmental disability, who were born with a birth defect."
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Biden says GOP advocates for special needs kids should support stem cell research
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McCain camp says Biden "sunk to a new low" with comments
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GOP VP pick Palin has a son with Down syndrome, opposes stem cell research
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Biden spokesman says vice presidential nominee did not target Palin
@placeholder signed a bill this year increasing special needs funding but frustrated some of the bill's co-sponsors by stepping in only at the last minute.