The chromosomal complements of a fetus can be determined by analysis of cultured amniotic fluid cells obtained by amniocentesis. Prenatal cytogenetic studies are presently indicated in three situations: history of a previous child with aneuploidy, increased maternal age, and a parent with a balanced translocation or an inversion. A major goal of reproductive geneticists is to identify individuals who have an increased risk of having offspring with chromosomal aberrations and, hence, to whom prenatal cytogenetic diagnosis should be offered.
