In the vast majority of CAH cases (due to 21-hydroxylase or 11-beta hydroxylase deficiency), kids will make too much too testosterone, unless properly treated (as Sprite said.)  

However, there are some cases where CAH is caused by the deficiency of a different enzyme (such as 3-beta dehydrogenase or 17-alpha hydroxylase).  If that is the case, then the child will make too little testosterone.  Then I think the child (boys) may very well be given testosterone shots as they near puberty, though I don’t know the details.

Has your son been diagnosed with CAH?  What type?