Gender selection is available for patients who wish to select the sex of the embryo used in their fertility treatment. The sex chromosome found in the sperm is the determining factor for gender. Unfortunately, methods to sort X (female) from the Y (male) sperm are still inaccurate due to limitations in current technology.
For patients who want to be certain of the gender of their embryo, Preimplantation Genetic Diagnosis (PGD) can be used. This is a more intensive process that involves the examination of embryos during the time when they are developing in the IVF dish. Once the fertilized egg has reached the 5-6th day of development (called a blastocyst) a few cells can be safely removed for testing. If a Y chromosome is present, this indicates that the gender of the embryo is male. This procedure has a 99% accuracy rate for gender selection – significantly higher than with sperm sorting.
PGD also offers the opportunity to screen an embryo’s chromosomes for errors prior to implantation. Women who have passed the peak of their fertility have fewer eggs and these often give rise to chromosomal abnormalities. Embryos that develop with chromosomal errors almost always result in early miscarriage since few defects involving chromosomes are compatible with life.
Preimplantation genetic diagnosis improves the chance that any embryos used in In Vitro Fertilization have a normal chromosome count and that there are no errors in the combination of chromosomes. Gender selection can be done at the same time if desired. The screening process is almost 100% accurate for identifying healthy, normal embryos. It is not intended to be a guarantee against birth defects since most defects that result in live birth are caused by other factors during the pregnancy. Instead, the purpose of PGD is to ensure that an embryo is viable and likely to thrive upon implantation. This significantly increases the chances of successful In Vitro Fertilization treatment.