Kati - I understand your concern, but I wouldn't worry overly much about it. My daughter has CAH. I have 6 brothers and 7 sisters; 18 neices and nephews; and among my neices and nephews there are another 10 children... not one of them has CAH. I would mention it in case your brother wanted to be tested; but I wouldn't do it in such a way as to cause a big scare. Remember, CAH is not that common, and BOTH parents have to be carriers in order for a child to have the disease.