Hi, if a person who has CF has a child with a person that doesn't have CF and doesn't carry the CF gene then the there is a 100% chance of the children being just carriers. If the CF person has a child with a carrier eache child has a 50% chance of having CF and a 50% chance of just being a carrier. I have info about genetics on our site. go to http://groups.msn.com/teamRachelJane look on the left and scroll down you will see a page about basic genetics. more in depth explanations and combinations. Andrea