Thoughts On The Phrase "Grow A Pair"

At the risk of losing the few readers I have that still tune in to Bookpuddle from time to time and wonder….. "Umm, why is this guy pretty much never talking about books anymore"….. umm -- let me now make the situation a few magnitudes worse. Just a few words about… testicles.
Or more specifically, that thing that people say when they are berating someone that is not "manning up" or being "tough enough".
You've maybe used the phrase yourself now and then, or at least are familiar with it -- people that think someone else is being a "wimp" say [and there's no question mark at the end of it, so it isn't even really a proper question], they say -- 
"Why don't you grow a pair!"
A pair of what? Testicles?
The majority of my Bookpuddle readers are women, but let me assure you, as a man with two perfectly good… [those things] -- I can 100% guarantee you that the last thing I would ask for, to make me TOUGHER, or more invulnerable -- would be like, to acquire somehow… more testicles.
Two are already way too many.
In all seriousness, a five-year old kid could completely debilitize Arnold Schwarzenegger if he or she landed a good kick in the right place. So I am not sure what people mean when they say "grow a pair." They must mean that, in the first place…. you did not have any? That is the only explanation. But even that does not make sense. 
Because really, you would be some sort of super-hero if you did not have any at all.
I can understand what it means to grow a "pear"…. but growing a "pair"?
An extra one, like?
It would not help matters. Not at all.
Like having four or six of these things? I would not ever leave the apartment.
I promise -- my next blog-posting will be about books.