Cystic fibrosis (CF) is the most common genetic disease among Caucasians. Duchenne muscular dystrophy (DMD) is one of the most common X-linked genetic disorders. The CF and DMD genes were discovered a few years ago, which provided the possibility for prenatal diagnosis and preimplantation diagnosis of CF and DMD by using specific DNA analysis. In this article, CF, DMD, the process of the identi...