At the moment I am about 5 ft 9 having grown recently this summer. I'm 17 and my voice has broken, I would say. I have hair growing on my face, but only on my upper lips. I have tons of pubes and ball hair and a half decent amount of arm pit hair; however, my balls and penis haven't grown at all. I can get an erection whenever and can ejaculate. Should I see a doctor about my child-sized balls?
From the information, it looks like you were a late bloomer. You are at the end of Stage 3. That means your penis and testicles are still growing. Though your genitals are not as large as you dream they would be, they are still functioning. I sincerely doubt that your genitals are as small as a child's or haven't grown. Children can't have erections and ejaculate, so some growth has taken place.
There really isn't anything a doctor can do about the size of your genitals. Some men are bigger and some are smaller. Just as some men have big feet and some have small feet. It is considered normal for a man's erect penis to be anywhere from 3 inches to 8 inches. The average is 5.2 inches but remember that is average -- half are bigger and half are smaller [http://www.bjuinternational.com/bjui-blog/normal-review-analyzes-data-flaccid-erect-penis-lengths-men/].