When we got tested,  I have two SW CAH boys,  this was prior to my second son being born.  Anyway my husband was supposedly not a carrier,  that means they could not find a mutation on his gene.  Anyway,  they tactafully were asking me if he was for sure the father,  he is the father, and my kids look excactly like etc....so sometimes they can not identify the genes.  My endo will not treat based on DNA testing,  he waits until they present with symptoms etc....it drove me nuts at the time because we were 99% sure my second had  SW CAH but he said they are wrong sometimes.  My second does have SW CAH too, and started on treatment about 4 days old. 

My boys are 5 and 8 and are doing great!