[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/09/09/art.palin.biden.gi.jpg caption="Was Biden referencing Palin in his comments about stem cell research?"](CNN) - John McCain's campaign hit back hard at Joe Biden Tuesday after the Democratic VP candidate appeared to suggest Republicans who do not support stem cell research - like GOP VP candidate Sarah Palin - are lacking in their support of children with disabilities.
“Barack Obama’s running mate sunk to a new low today launching an offensive debate over who cares more about special needs children," McCain-Palin spokesman Ben Porritt said. "Playing politics with this issue is disturbing and indicative of a desperate campaign."
The sharp response, indicative of the increasingly heated rhetoric from both presidential campaigns as the election enters the final stretch, came shortly after Biden said advocates for people with disabilities should support stem cell research.
Biden did not mention Palin - the mother of a baby with Down syndrome, and someone who has said she will be a “friend and advocate in the White House" to parents of children with disabilities - but seemed to direct a question to her.
Election Center: Where the candidates stand on stem cell research
“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,” he said. “Well, guess what folks? If you care about it, why don't you support stem cell research?”
Biden spokesman David Wade insisted Tuesday the Delaware senator's comments were not directed at Palin.
"This is a clash of policies, not a clash of personalities," Wade said. "We've heard not a dime's worth of difference between the McCain-Palin ticket and the Bush Administration on medical breakthroughs that millions of parents and doctors believe could save lives and transform the quality of life for countless Americans."