Your boss
Many employers require drug tests. They’re intended to weed out addicts, people so hooked on their substance of choice that they can’t lay off for a couple days before filling the little cup. Those people tend to be unreliable, and in some workplaces can be dangerous. As gene sequencing becomes cheaper and cheaper, we can imagine a day in the very near future when a prospective employer requires applicants to submit their sequence. There, the markers for addiction, alcoholism, insanity, and chronic diseases that might affect performance could be noted and attached to your file. Someday very soon you might lose your job (or never get one) not because you’re a drug addict, but because you could be.