The PCR methods for carrier and prenatal diagnosis of Duchenne and Becker muscular dystrophy are described. When a deletion of the dystrophin gene is detected in the proband, the deletion analysis is informative for prenatal diagnosis, and the quantitative PCR analysis of the concerned exons is necessary for carrier diagnosis. When a deletion is not detected, RFLPs analysis should be considered. We analyzed seven polymorphic makers (pERT87-15 combined with digestions with BamHI or XmnI, pERT87-8 combined with digestion with TaqI, and four CA repeat markers at the 5' end and the 3' untranslated regions of the dystrophin gene) by PCR methods. Every woman examined showed a heterozygous finding for at least one of these markers, making it possible to make carrier and prenatal diagnosis. However, it is important to keep in mind that a third of the patients are due to new mutations and that about 10% recombination rate, between the 5' and 3' ends of the dystrophin gene, can exist.