Amniocentesis is the process of removing from a pregnant woman's uterus a sample of the amniotic fluid which surrounds the fetus. This fluid contains fetal cells which are analyzed to identify genetic defects of the fetus. Until the advent of amniocentesis, prenatal diagnostic techniques were severely limited. In February 1952, the English physician Douglas Bevis published an article in the journal Lancet describing his use of amniocentesis to identify risk factors in the fetuses of Rh-negative women whose partner had the Rh-positive blood type. Bevis, who conducted his study at St. Mary's Hospital in Manchester, England, chemically analyzed the iron and urobilinogen content of the fluid to determine the possibility of hemolytic (blood) disease in the unborn child. While the technique of using a needle to obtain samples of amniotic fluid was available in the late 1920s or early 1930s, the Bevis study is considered a landmark that led...