Amniocentesis has been the primary technic of diagnosis in this beginning era of fetal medicine. Two of the new applications have already demonstrated exciting potential for a much expanded diagnostic and therapeutic approach to the human fetus. One is ultrasonography whose sophistication now provides detailed representations of both surface and internal organ anatomy. The second advance has been the development of fetoscopy and fetal biopsy. With these technics parts of the fetus can be visualized directly using light brought into the uterus. Fetoscopy with currently available instruments has definite limitations. Severe abnormalities of surface anatomy can be recognized, but small variations from normal cannot. Blood sampling via fetoscopy is somewhat more difficult when the placenta is anterior but can be satisfactorily accomplished with experience. Duchenne muscular dystrophy is the most common and severe muscular dystrophy of childhood. It is an X-linked trait and thus disease is seen almost exclusively in boys.