Philadelphia Enquirer science writer, Faye Flam, examines how the desire to 'score' has profoundly shaped males over millions of years. Sweeping from the origin of the sexes to the sexual foibles of 21st century humans, Flam shows how a small difference in the size of the first sperm and eggs resulted in an evolutionary trade-off that has affected both males and females. Within this tug-of-war context, Flam explores a wide range of male behaviours and courtship strategies and ultimately reveals that males have been shaped by competing for the favours of the female sex.