HELEN BEQUAERT HOLMES AND
Methods of ensuring fetal sex before conception, most of which are unreliable, involve the separation and the elimination or enhancement of female- and male-determining sperm. Techniques include the timing of intercourse, special douches, electrophoresis, position during intercourse, and diet. Franchised clinics and sperm firms have been opened throughout the world, featuring a method of separating sperm (the Ericsson method) that is claimed to be about 85 percent successful. In the 1990s, preimplantation diagnosis has been a focal point of research, as has been a search for a sex-determining gene. However, although researchers seek methods of sexing preimplantation embryos that will not harm the embryo, much less concern is shown for the women involved. Preimplantation sexing requires in vitro fertilization and highly invasive and potentially risky procedures. Currently the sex of a four-to-eight-cell human pre-embryo (about one day old) can be ascertained by detecting whether it has a Y chromosome.
If sex selection is to occur later in the reproductive cycle, it requires abortion. In the first trimester, methods are under development to sex fetal cells in maternal blood. There are drawbacks to this method, however. First, in the case of female fetuses, markers are required to prove that the cells are of the fetus and not of the mother. If the fetus is male, the mother must never have had a previous pregnancy (successful or not) with a male fetus because some cells from that fetus may still be circulating in her blood. Another method of sex selection after impregnation is to sex