Best way to talk to a doc is to self-educate as much as possible first. Read all the stickies here, review your blood work. Get copies of it if you don't have it and post it up, we can review it for you. Tell us your age and stats please.
Also, did your doc give you a clue why you are low? Many things can cause low T that are correctable without going on TRT. It's always best to know exactly why before you embark on this path. If you choose to not go with your doctors recommendation of an endo or uro you can always check out
Low Testosterone - $199 All-Included Testosterone Treatment which is owned by this site and focused on TRT. Most regular doc's, endo's, uro's are not.