Why Do Girls "Throw Like a Girl?"

I've got a serious question.  Why do girls throw like a girl?  I don't understand.  I mean, have you ever seen a girl that doesn't throw like a girl?  I haven't done a ton of study on this, but what is it that makes girls throw like a girl?

Sometimes boys throw like a girl, too. I think that Phillip Rivers of the San Diego Charges throws like a girl, but a girl that can throw a ball super far, and he's an NFL quarterback.  I'm not saying girls can't throw a ball, because they can, but I don't think I've ever seen a girl throw like a boy.  Is there something structural with the elbow and shoulder that is different in boys and girls that makes them throw that way?  And you know what I mean, it's that sort of shove/throw thing, where girls sort of lean into it.  I throw like a girl when I throw left-handed, because I'm right handed and I don't know how to throw with my other hand.

And that's another thing, what's up with handedness, anyway?  Why are we dominant with one hand over the other?  Don't you think that evolution would have made us ambidextrous by now?

I wish I had the answers here on this blog, but I don't.  I guess I'm seeking answers.  If you have an answer, hit me up in the comment section, or perhaps leave a comment on Facebook.  Whichever is easier for you.  I need to know.