Intra-uterine Diagnosis of Fetal Sex

The ability to examine amniotic fluid obtained by amniocentesis during the second trimester of pregnancy is a significant new advance in the practice of clinical genetics.1 We here report a rapid and accurate method for determining fetal sex, which should be useful when the pregnant woman is a carrier of a serious sex-linked disease such as muscular dystrophy or hemophilia. The method makes use of the selective concentration of fluorescent stains by the Y chromosome in interphase cells.2,3 Recently two observers have reported their preliminary observations on amniotic fluid cells using fluorescent techniques.4,5