Prenatal diagnosis and carrier detection for Duchenne muscular dystrophy (DMD) usually can be performed using DNA analysis. When recombination occurs within the DMD gene, or DNA analysis is uninformative, or in pedigrees where it is unclear whether or not the consultand is a carrier, direct examination of muscle by dystrophin analysis may provide the only means of prenatal diagnosis. We present three cases representing each of these molecular genetic diagnostic dilemmas. In each instance, we used sonographically guided fetal muscle biopsy for dystrophin protein analysis to resolve the dilemma. In the first and third cases, the presence of normal dystrophin was shown by immunofluorescence and this was followed by delivery of an unaffected male fetus. In the second case, dystrophin was not found in fetal muscle tissue implying that this fetus was affected. The absence of dystrophin and affected status was confirmed in skeletal and cardiac muscle obtained after pregnancy termination.