Stay your rage for a moment. Female Genital Mutilation is mostly confined to Africa where it has a (despicable) pre-Islamic tribal tradition, much like most of the mysoginst crap Shariah law in the Middle East. However, there is little tradition of FGM in Middle Eastern cultures. ISIS maybe filled with sons of bitches who make the trains run on time, and it is possible they did make this edict, but I am holding off on my rant until this is verified.
I will add that it interests me that Islam is now approximately 1470 years old. When Christianity was about 1500 years old, it went through the Protestant Reformation. I think Islam is due for a similar purge of ideas, and left to their own devices (rather then Western nations presenting Islamic leaders with outside scapegoats to blame) they just might.