5-year old boy to become a girl: Right or wrong?

I read this morning about the story of a boy who at the age of three started dressing up as a girl. The boy now five years old lives his life as a girl with the full support of his parents, doctors and even the school. Psychologically, he was diagnosed to have GID (Gender Identity Disorder): a conflict between a person's physical gender and what they identify as. Hence, the boy feels like a girl trapped in a boy's body. 

This is not the first of its kind as the boy happens to be one of many other children affected by GID in the UK who in their heads think they are girls. According to a foundation Trust in London, 165 children received a GID diagnosis in the past year, of which only seven were under the age of five.

Although I'm not an expertise in this field, I feel it is just too soon to allow this boy go through it. He is just only 5years for heaven's sake! Does a 5-year old know what this means for him? Perhaps he has a lot of girls around him and just want to play around trying to dress like them, and not necessarily because he wants to change his gender. I think the parents need to think it through and let the child understand that there is nothing wrong being born a male or a female. The boy needs to be allowed to grow up like a male that he indeed is. Truth is you can never genuinely experience what it really feels like to be a male or a female if you are not born that way. Simple as!

So my question is why encourage him at such a tender age? Why not give him some counselling to make him understand certain things and see if, when he becomes an adult he still feels the same way? I feel they should let him enjoy growing up as a boy because he was born that way and he is too young to understand certain things in life. The worse thing would be for him to have a sex change and regret it when he grows up.