The dramatic physical and behavioral differences between men and women including strength and size pubertal timing consistent patterns around the world of hunting versus gathering and. Sexual dimorphism is a term for the phenotypic difference between males and females of the same species through the process of meiosis and fertilization with rare exceptions each individual is created with zero or one y chromosome the complementary result for the x chromosome follows either a double or a single x. Due to the genetic differences individuals belonging to two sexes are born differences in the sexes are based on differences in the makeup of their sex chromosomes it is well known that females have two similar chromosomes x x while males have two different chromosomes x y. In most animals from bees to bulls mice to men it is possible to see at a glance whether an individual is male or female how and why these differences in appearance and behavior developed and the nature and extent of the differences between males and females is a complex subject this book reviews the latest molecular genetic hormonal anatomical and behavioral data in a wide range of