Experts are still debating the answers to that question. We do know that all human beings can be violent given certain circumstances, such as war. We also know that while not all men are violent, men in general tend to be more violent than women.
Biologists cite the male hormone testosterone as a kick-starter for aggressive behavior in men.
While the hormone affects male attitudes and the propensity toward violence, they stress that as humans, we make individual choices whether to be aggressive or not. Violence against women has been accepted and even condoned throughout history. More than 2,000 years ago, Roman law gave a man life and death authority over his wife. In the 18th Century, English common law gave a man permission to discipline his wife and children with a stick or whip no wider than his thumb. Many feminists claim violence against women is the result of a deeply entrenched patriarchal culture that encourages and rewards male domination.