Hi,
Welcome to health care magic, i hope you find your answers here.
Well, what you are trying to say is
micropenis or microphallus. Actually, penile length cannot be assessed just by looking at it.There is something called STRETCHED PENILE LENGTH (measured from pubic ramus to the tip of the
glans while the penis is stretched).A normal adult male has a SPL = 9.3cm average.
Besides i would even like to know your son's height and weight. Sometimes if boys are
overweight, they have a large amount of suprapubic fat and the penis is actually burried in this fatty area and LOOKS small, though actually is of right length.
I would advise you to check the correct length as i have told you and if still you think it is short, you should see an
endocrinologist just to get the other features of secondary sexual characters verified.The testicular volume and pubic hair are important too.
I am sure you wont have to go to the doctor after correctly checking the length of the penis. Hope your doubts are cleared as on now.
Will always be available to answer your querries....Take care.