What you have said should ring warning bells. CAH children are almost always shorter than average. If your doctor is underprescribing Cortef, which will increase your son's androgen levels, then he will grow faster now, but "use up" his growth too soon and stop growing at around 5'4" or so (maybe less). Both Jonathan and Ginny have always been on the bottom edge of "normal." My wife is 5'3" and I am 5'11". I would seriously urge you to get a second opinion as soon as possible.