An especially tragic case shows that effective self defense often requires a gun. On October 20th, 2008, KATV anchorwoman Anne Pressly was found unconscious and severely beaten in her own home, with every bone in her face broken. Days later, she died without ever regaining consciousness. A police investigation determined that she was robbed and sexually assaulted by her attacker. Police believe that she was the victim of a random home invasion robbery. It was also revealed that she apparently broke her hand while trying to fight off the attacker, in a commendable but ultimately unsuccessful attempt at self defense. A suspect was later arrested and is awaiting trial.
At the very least it shows that hitting people with your hands is only a good idea if your hands are genetically adequate for the task. Mine aren't so, as Bill Wallace used to say, I use my hands to push people away so I can kick them. Actually, the Yang 'classic' Tai Chi form is well suited to knee and elbow incorporation and you can definitely hit a lot harder without risking self-injury using knees and elbows than you can using your fists.