What do you really know about your testicles? Most men know surprisingly little about how their reproductive system works, despite it playing a vital role in fertility, hormones, sexual health and overall wellbeing. In Your Nuts, reproductive scientist Michael Carroll takes readers on an engaging journey into the remarkable biology of the testes. Drawing on nearly three decades of research and clinical experience, he explains how sperm are made, how testosterone is produced, why fertility is changing, and what lifestyle, environment and health mean for male reproductive function. Combining the latest scientific evidence with clear, engaging explanations, this accessible guide explores what we know, what we still don't know, and why understanding the testes matters to every man. Along the way, it separates evidence from myth, answers the questions many men have never thought to ask, and challenges some of the most common misconceptions about male reproductive health. Whether you're planning a family, curious about your own health, or simply want to understand one of the least discussed organs in the human body, Your Nuts provides an authoritative, evidence-based and entertaining guide to one of the most fascinating - and misunderstood - parts of the male body.