If a girl hits a guy, does the guy have a right to hit her back?

[Mummelmann]

I do feel that women today get off too easily with crap like that, but I'll never hit a girl for any reason besides saving my own or someone else's life.
It would feel wrong, I'm a big man, 6'5" and over 260 pounds so it'd be really cowardly of me, and I hate guys who hit girls, I've seen it too many times.
Women need to realize though, that just because its common courtesy not to hit them, they may get slapped back if they start it and its really rude and childish to take advantage of these age old tenets to hit guys just because you know people will react if he hits back.