When I’m in the lab extracting and isolating a piece of DNA, I’m always in awe of how these tiny bits of genetic material hold the instructions to life. The DNA in our cells replicates every time a cell divides. The process is precise and reliable—until one day, it isn’t. That faulty copy can mean a mutation like blue eyes that appeared in humans thousands of generations ago. It can also mean cancer. My sister Aleeya and I share DNA inherited from our parents. We both have brown hair, wide smiles, and are fiercely competitive. But when Aleeya developed leukemia ten years ago, I didn’t know what DNA was yet. All I knew was that my three-year-old sister was sick, and she and my mother would spend long stretches of time at St. Jude Children’s Research Hospital in Memphis. My dad stayed behind with my middle sister and me. He was a truck driver, so our grandparents or aunts took care of us while he had to go on the road. Sometimes, though, we would all make the four-hundred-mile trip to visit Aleeya. I remember how small she looked in the hospital bed, a tube strapped to her arm, her curly, brown hair still covering her head. The chemo would come for that later. It was those visits that sparked my interest in the healthcare profession. Aleeya had one of the top cancer doctors in the country—really, in the world. I remember being in awe of him. He was mesmerizing. I was comforted knowing he was taking care of Aleeya, and that people like him were doing as much as possible to help. Now that I’m older, I understand how good a scientist and doctor he was. Watching him translate that information with such kindness and ease was inspiring. After that experience, I knew I wanted to help other people navigate difficult times, just as he helped us. ...