CNN

Watch the Mcain-Palin event on CNN.com/live.

COLUMBIA, Missouri (CNN) – Joe Biden suggested Tuesday that advocates for people with disabilities should “support stem cell research” - a remark that follows repeated pledges from Republican VP nominee Sarah Palin, the mother of a baby with Down Syndrome, to parents of children with disabilities that she would be “a friend and advocate in the White House.”

When asked about the issue at a Tuesday rally, Biden did not mention Palin’s name, but seemed to direct a question to her.

“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?”

Related: McCain camp says Biden 'sunk to a new low'

Biden told voters “the disability issue is not a new issue for us” and said he and Barack Obama would support stem cell research — a political hot potato that Sarah Palin does not support because it involves the use of human embryos.

In an illustration over the controversy of stem cell research — a key issue for some conservative voters — the Republican ticket is split. John McCain supports the practice.