Most hopeful parents would be delighted to have an infant of either gender, boy or girl. However, for various reasons, some have a strong preference for one gender over the other. We see this arise, for example, for cultural reasons or when a family already has multiple children of one gender and just wants to achieve gender diversity.
This is not new. People have tried to control the gender of their conceptions since long before IVF came along. For example, some believe that having intercourse a certain way will control the gender of offspring. This idea appeared to be supported by the fact that the X (female) or Y (male) chromosome from the sperm determines the gender of the embryo (the egg, or oocyte, always carries an X chromosome). Because the Y chromosome is smaller and therefore lighter than the X chromosome, some believe this allows sperm carrying the Y chromosome to swim faster. In practice, this difference is too small to matter, and such techniques do not produce substantially more infants of either gender than would be expected otherwise. Gender selection techniques that rely on differences in the sperm’s swimming speed are not very effective.
With IVF, we have the ability to examine the genetic make-up of an embryo. We can check embryos in culture for diseases carried on the chromosomes (single-gene defects), like cystic fibrosis, for example. We would then transfer to the uterus only those embryos that do not have the disease-carrying gene. We can also check the number of chromosomes in each embryo, and transfer only those with the normal number. It is hoped that this approach will increase IVF success rates per transfer by eliminating transfer of non-viable embryos. These genetic tests are commonly known as PGD or PGS (pre-implantation genetic diagnosis or screening).
PGD and PGS also reveal the embryo’s gender, allowing gender selection. Female embryos have two X chromosomes (one from each parent) while male embryos have one X chromosome from the mother and one Y chromosome from the father. The transfer of only those embryos of one gender will greatly increase the chance that any resulting children would be of that gender. This is a very effective technique for gender selection.
The Fertility Center of Las Vegas has used PGD/PGS for gender selection for more than a decade.
To learn more about gender selection, call The Fertility Center of Las Vegas at (702) 254-1777 and ask to speak with an IVF coordinator.
