The more comprehensive our DNA database, the more useful it is for identifying perpetrators and lifting suspicion from innocents. By excluding persons never arrested, our database will come to hold DNA profiles of nearly seventy-five percent of adult males and ninety percent of black males. Privacy is threatened not by the database but by government retention of tissue samples after analysis of the tiny fraction of DNA that yields the uniquely identifying profile. Public safety and privacy would best be protected by routinely destroying samples while deliberately constructing a comprehensive database.