The purpose of this project is to develop a safe, relatively inexpensive, accurate and non-invasive technique for the prenatal diagnosis of genetic disorders by isolating fetal cells in maternal peripheral circulation during the first trimester of pregnancy. Separation will be accomplished by flow cytometry with trophoblast antibodies and HLA antibodies. Methods will be developed for culturing fetal cells. Fetal aneuploidy and polyploidy will be detected by measuring fetal cellular DNA with flow cytometry (DNA indexing), a sensitive method developed by the investigators. These techniques can be used for the prenatal diagnosis of cytogenetic, biochemical or DNA abnormalities.