Abstract
This chapter examines a study on the influence or the role of hormonal, sexual, and genetic factors in aggression. The findings reveal that genetic factors have more of a preparatory role when they contribute to the development of sensory capacities, body size, and motor functions needed for effective aggression. The results also indicates that males are usually more aggressive than females, and that testosterone and the female hormones, prolactin and estrogen, are linked to increased aggression.