President Bush has said he wants Osama bin Laden dead or alive, but there's one problem with getting him dead: how to positively identify a tall, bearded corpse as the real evildoer. FBI lab experts stand ready to run DNA tests on the remains. But they don't have a sample of DNA known to have come from bin Laden. The solution? Officials say they will seek tissue samples from his immediate relatives, most of whom, including his mother, are living in Saudi Arabia. Matching what's known as mitochondrial DNA to that of his mother would provide the most definitive identification, since bin Laden is thought to be the only child of his mother and the bin Laden family patriarch, who has many wives. The chief stumbling block may be the willingness of the Saudi regime to allow the DNA hunt. Just another challenge for U.S. diplomacy.