So how old is John McCain? Six-packs of beer, automatic transmissions and the American Express card were all introduced after he was born - not to mention computers, which McCain admits he doesn't use. McCain, himself, jokes that he's older than dirt. And while his age is being raised as a campaign issue, medical experts say voters shouldn't be concerned that, if elected, McCain would be the oldest man to assume the presidency, at 72. In politics and other fields, they explain, it's not unusual for talented people to do signature work late in life, when they can apply the cumulative wisdom of experience, and leverage personal connections cultivated over time. Nonetheless, a significant slice of the electorate has qualms about McCain's age. The presumed Republican nominee will celebrate his 72nd birthday shortly before his party's convention. Polls show the age question isn't going away, despite the Arizona senator's efforts to deflect it with self-deprecating humor, or disprove it by keeping a grueling schedule.