You have an aura, except it isn’t made of purplish light; it’s your personal cloud of dead skin cells, fungus and many, many microbes. And researchers are learning to be able to identify you by it. Trillions of bacteria live on and in the human body. Together, these bacteria make up what researchers call the human microbiome. A new study out of the U.S. determined that an occupied room is microbially distinct from an unoccupied one also showed detectable differences between people’s microbial cloud “signatures,” including identifying their gender.