The present study was undertaken to evaluate a polymerase chain reaction (PCR) for detection of Y chromosome-specific fetal DNA in maternal plasma of pregnant women during different gestational stages. DNA isolated from plasma samples of 90 pregnant women (between 7 ADN 40 weeks' gestation) underwent specific DNA on the Y chromosome (DYS14) gene is amplified and house keeping gene GAPDH (glyceraldehyde- 3-phosphate dehydrogenase) gene as internal control were amplified simultaneously in' the PCR reaction. The postpartum analysis of fetal gender showed that 54 women carried male ADN 36 female fetuses. Among the 54 women bearing male fetuses, Y chromosome-specific signals were detected in 53 (98,1 percent) plasma ADN samples, 36 cases of pregnant women show no detection of gene DYS14. Internal control GAPDH gene is amplified in the 90 case studies. This demonstrates that the process of extracting fetal freedom DNA in maternal blood, the authors achieved good results and this will be a useful approach to disease diagnosis and genetic screening on autosomes and sex chromosomes as a non-invasive method in the future. The application of this result the authors conducted diagnostic disagreement between mother blood and fetal blood by PCR on RhD gene of mothers has the Rh( -) blood groups. Results showed that 7 out of 9 patients pregnant Rh (+), 2 of 9 patients pregnancy fetal blood group matches with the mother's blood.