The Real Ryu Hi
I voted for the girl, and here's why: science has shown females have higher endurance levels than guys, thus meaning they can take more of a beat down than a guy and can last longer in a fight. Additionally while men on average are stronger, women are faster, thus indicating you can only hurt what you can hit.
Except speed and accuracy are completely separate. I myself have high speed, high dexterity in my fingers. Though I have low accuracy with my fist. Plus I wouldn't actually fight a girl as I am a real man and not a boy.
That said, the my dad can beat up your dad type of argument is pointlessly juvenile. Because whoever wins, it certainly doesn't change anything.
So, a Man vs. a girl/women = no fight at all.
A boy vs. a girl/women = a completely shallow victory. Plus they loose something in all cases.