i have two kids, both much younger than yours, so they don't really understand yet. anyway what i tihk you should do is gather all the info on transsexualism that you can and have him read it. then if he has any questions, answer them the best you can. if you can't answer his questions, try looking for them with him. the best place to tel him is a neutral place where you both feel comfortable and he's not going to make a scene. from what i have seen and heard, most children when younger are more accepting of a person's transsexualism. he may not accept it at first, if at all. the best thing is to not rush this past him and let him know the process will take time. the other thing you could do is if he has questions, you can refer him to us on this site and we may be able to answer some of the questions he may have. he will find we are more than willing to help people no matter what their situation is. i hope this helps and wish you well on your journey....
Best wishes,
Mickie