There are pros and cons to neutering and they should be considered. If you're having no behavior issues due to his being intact and you have good control over him, then I would think that most of your concerns would be health related.
Here's a link that provides some info on the health risks and benefits of neutering.....
Health Risks and Benefits Associated with Spay/Neuter in Dogs
You will find similar info if you do a google search along the lines of 'risks and benefits of spaying and neutering dogs'.
The other thing to consider is the risks of the procedure. Pre-op bloodwork and the use of a safe anesthesia will minimize those risks. Here's a link to a sticky here at YT that goes over anesthesia protocols....
http://www.yorkietalk.com/forums/yor...-protocol.html