WE are having our 2nd baby(first trimester). The doctor told my wife that the CF gene was detected in her, now, and I should be checked for it. ???? Can the gene lay undetectable during/before the 1st pregnancy (since the doctor did not say anything about it) and not become more active during the 2nd pregnancy. The first child, as far as we know, does not have CF (if the hostipal vefired corectly at birth). I would be surprised if the gene is like a virus, undetectable, until a special condition occurs to make it come out. I do not have anybody in my mothers(9 siblings) and fathers(5 siblings) with CF active. My wife's family is also negative for active CF. COULD THE FIRST PREGNANCY HAVE CREATED A FALSE NEGATIVE AND THE 2ND PREGANACY A POSITIVE?