To the Editor.— A recent situation pointed out for me a possible abuse of prenatal chromosome evaluation of the fetus. The patient, a 38-year-old mother of one boy and two girls, asked her obstetrician for an amniocentesis to rule out Down's syndrome. He collected and sent a specimen of her amniotic fluid to my laboratory where, subsequently, a chromosomally normal female was diagnosed by karyotype analysis from two different culture flasks. The diagnosis was also confirmed by smears for sex chromatin body and fluorescent stains for the Y chromosome. When the patient was given the news she stated that she did not wish to carry a female child and sought a therapeutic abortion. It became obvious after discussing the matter with the patient and her husband that they desired another son and had decided on this course of action to insure obtaining this goal. This situation may well become a