In other words: doing their job. And the McCain camp is appalled:

A senior McCain campaign official said the McCain camp was appalled that these rumors had not only been spread around liberal blog sites and partisan Democrats, but also were the subject of heightened interest from mainstream news media.

Now they've cleared the air on this - and good for them - what harm would it do to release the medical records showing that Sarah Palin delivered Trig on April 18 in Wasilla? This is not hard: there must be an obstetrician, medical records, and data that can easily refute this rumor. It is not out of the ordinary either: candidates routinely issue medical records. So let's have them. And then we can move on.