A geneticist tells the stories of men, women, and children whose genes have shaped their lives in unexpected ways.

It was while listening to a colleague tell the parents of a newborn girl that their daughter was going to die that a lifelong interest in genetic medicine was sparked in Dr Edwin Kirk. Warmth and gentleness tempered a direct, sure manner — this was the medicine he wanted to practise, where the most advanced science and the most deeply human meet. Twenty-five years later, Dr Kirk works both with patients and in the lab, and he spearheads a campaign that will change the way we think about having babies. His experience is without parallel, but it is his humour and insight that make all the difference.

Find out why Dr Kirk found himself among hundreds of people, each with a glass of poison in front of them — and how you might perform the same experiment yourself (without the poison). Learn how the realisation that a young boy wasn't short ended up saving the life of his mother — and how Angelina Jolie has saved the lives of many more. Sit in the room with Dr Kirk and his patients as they navigate the world of heartbreaking uncertainties, tantalising possibilities, and thorny questions of morality. In genetics, it is the particularities of an individual's history that matter, and here, in clear and considerate writing, those individual stories are given voice.