Why can't I cry?

You can't really deny that women do, on average, cry more than men.

Could that be because MEN AREN'T ALLOWED TO?

I'm definitely not one of those who believes that crying is a weakness to be hidden (applying to both sexes).  I am just not remembering when was the last time I shed a tear.  

Why can't I cry?  (rhetorical....I know no one has the answer)

Thankfully, I have laughter, or I might as well just go insane!