Reiterating his call for joint town-hall meetings, McCain added: "If Senator Obama wants to make a statement like that while we're both on stage or before a group of Americans, then I will be glad to respond to him. I think my record speaks clearly for itself."
McCain is an opponent of abortion, a stance that hurts him with some female voters and among Democratic constituencies.
The Hill, a Capitol Hill newspaper, reported Thursday that Obama made the comment last week during a private meeting with members of the Congressional Black Caucus.
An Obama spokesman said he had no immediate comment on the report.