<human>: This is something I've given a lot of thought to.  In most of the world, it is generally accepted to automatically amputate extra appendages.  I can see the benefits to this, in the sense that the child might be ostracized or harassed because of his deformity, and it might cause physical disabilities later on.  
However.  This is the question I pose to you, Reddit.  If your child was born with 4 fully functional, non-debilitating arms, would you have them amputated or not?
Personally, there is no way in Hell I would let them take away the opportunity for my child to be a superhero.  The first thing I would do would be to put him on a strict physical training regimen.  
1.  Exercise and weightlifting.  This child would be in perfect physical condition by his late teens.  
2.  Martial arts training.  Judo, jiu jitzu, kickboxing, tae kwon do, krav maga, Hell even boxing and street brawling.  Imagine this, my son or daughter walking down a dark alley, they get attacked suddenly by a mugger.  He pulls a knife, but is easily disarmed by my spawn.  With the top two arms, they grab the mugger's wrists while delivering crushing body shots to the criminal with the bottom set.  
3.  If, as I will let my child choose the manner to which he makes the world a safer place, he decides on law enforcement, then he will be trained extensively on firearms with all hands equally.  He will be able to hold four handguns at once, or two handguns and a shotgun/assault rifle, or my personal favorite: four Uzis. 
I can only think of extremely positive possibilities for this child, as I believe it would be a beautiful addition to the human genome, and hopefully the next step in human evolution.  

By the way, it's totally possible:

Give me a shortened version of the text
<bot>: if your child was born with 4 working arms, would you turn him into a superhero or amputate them like a horrible parent?