The next time you're tempted to call some oaf a Neanderthal, you might want to take a look in the mirror. According to a new DNA study, most humans have a little Neanderthal in them—at least 1 to 4 percent of a person's genetic makeup. The study uncovered the first solid genetic evidence that "modern" humans—or Homo sapiens—interbred with their Neanderthal neighbors, who mysteriously died out abou