The following is a review of current concepts of prenatal detection. Transabdominal amniocentesis is recognized to be an integral adjunct to prenatal care. The analysis of cultured amniotic fluid cells collected at about 16 weeks of gestation provides in utero diagnosis of nearly all chromosomal aberration syndromes, several metabolic disorders which are due to a specific enzymic deficiency due to single gene disorders, and some multifactorial disorders, such as prenatal diagnosis of neural tube defects by estimation of alphafeto protein in amniotic fluid. Various aspects of amniocentesis are discussed.