You should'nt hit somebody first but if you are hit, then yep, hit back! That said, no body should hit somebody first no matter what size each other is. Especially if you are the smaller one hitting a bigger person, expect to get hit hard.
And to all of the women out there that think it is ok to hit a man just because you are smaller than them and are a woman, is nutty thinking. I love the women that think they can haul off and hit there husbands and then freak out on them when they grab their hands off of them and then they go even more balistic beacause he touched me!! Ya, after you hauled off and hit him first!
Ladies, if it's not ok for a man to hit you, then it certainly isn't ok to hit a man either!!