Prenatal sex determination and selection.

The advent of the polymerase chain reaction technique has revolutionized the science of prenatal diagnosis including sex selection. The technique is now available to identify the sex of human preimplantation embryos after in-vitro fertilization or to determine the sex of a fetus by non-invasive methods. Where medical indication exists, selected female embryos can be transferred to the uterus and thus prevent unnecessary termination of an established pregnancy. However, these methods might be used for non-medical purposes as well. The developments in this field which have occurred during the last decade, as well as the moral dilemmas which accompany these advantages, are discussed in this paper.