It is most likely that just one of your parents is a carrier.   Approximately 1 in 50 people are carriers.  If both parents are carriers, the children have a 50% chance of being a carrier, and a 25% chance of getting CAH.  However it can happen otherways also.  My son has CAH, I am a carrier, but my husband is not????   The doctors can't explain it, they just says it's one of those odd cases.