Typical male sexual behavior is more assertive (e.g., the penetrative role). Typical female sexual behavior is less assertive (e.g., the receptive role). (Carter, Rita, Ed. Mapping the Mind. p 73. CA:University of California Press, 1998.)

Assertiveness/aggression is built into the male brain (e.g., related to testosterone). This is not true for violence, which is taught/learned. (Gurian, Michael. The Wonder of Boys. p 6-8. NY: Jeremy P. Tarcher/Putnam, 1996.)