If you are right-handed, pick up a ball with your left hand and throw it. Unless you are ambidextrous or have some other odd advantage, you will throw it "like a girl." The problem is not that your left shoulder is hinged strangely or that you don't know what a good throw looks like. It is that you have not spent time training your leg, hip, shoulder, and arm muscles on that side to work together as required for a throw.[...]
What Goodman discovered is what most men have forgotten: that if they know how to throw now, it is because they spent time learning at some point long ago...This brings us back to the roots of the "throwing like a girl" phenomenon. The crucial factor is not that males and females are put together differently but that they typically spend their early years in different ways. Little boys often learn to throw without noticing that they are throwing. Little girls are more rarely in environments that encourage them in the same way. A boy who wonders why a girl throws the way she does is like a Frenchman who wonders why so many Americans speak French "with an accent."