"You swab your cheek or spit in a vial, then send it away to a lab somewhere. Weeks later you get a report that might tell you where your ancestors came from or if you carry certain genetic risks. Or the report could reveal long-buried family secrets and upend your entire sense of identity. Soon a lark becomes an obsession, a relentless drive to find answers to questions at the core of your being, like "Who am I?" and "Where did I come from?" Welcome...