Rapid determination of fetal sex using amniotic fluid cells and the polymerase chain reaction.

We determined the sex of 50 fetuses by an amplification of the Y-chromosome specific fragment using the polymerase chain reaction (PCR). Amniotic fluid cells were collected by amniocentesis from pregnant women at 14 to 17 weeks of gestation. Total DNA was purified from cells in 1 ml of amniotic fluid. When only the expected 130 base pair X-chromosome specific fragment was detected, we identified the fetus as female, while when both the expected 170 base pair Y-chromosome specific and X-chromosome specific fragments were detected, we identified it as male. In all cases, identification was confirmed either by chromosome analysis or post partum.