If his genitals have been mutilated and such beyond use; he'll never be able to ejaculate or impregnate a women to have children anyway. So what's your point exactly, there's going to be something this child has to work through regardless of which decision anyone makes.
It's a shit situation to be put in, it's far to easy to sit outside of the weight of having this be your child and judge. Anyone who's ever judged something then been put in that same situation should be silent. Because they know it's never the same, and never as easy as it seems.
And Katz, there are actually people who try their hardest to be various animals they feel they identify with...so... but I don't quite get how a cat is the same as a person.
The child in THIS case has not been mutilated. His parents have given him a fantasy and demand that everyone else in the world treat their son in accordance with the fantasy they imposed on him. Don't confuse the issues. There nothing medically wrong with Coy. Actually, the parents likely had preplanned their transgendered son before he was born by giving him the name "Coy".
The point is that children, especially very young children, and 18 months is very young, are still learning and forming their identities. A cat is not the same as a person, UNLESS there are deranged parents who insist their child be treated like a cat, because that's the way their child identifies.