Sex selection is a procedure that can be done during an IVF cycle for patients who wish to choose the sex of their child.
Gender selection is a procedure that can be done during an In Vitro Fertilization cycle for patients who wish to choose the sex of their child. A typical IVF cycle is made up of 4 stages: follicle stimulation with hormone injections, egg retrieval, fertilization of eggs in an IVF dish, and transfer of one or more embryos into the patient’s uterus. The Gender selection step occurs after fertilization and before transfer. The technique used to identify an embryo of the desired sex is called Preimplantation Genetic Diagnosis (PGD). Unlike sperm sorting which does not reliably identify the sex of the embryo, PGD has been investigated and demonstrated to be effective. This technique has an accuracy rate of 99%.
When the developing embryo is 5 days old, it has many cells. Some of the cells will become the fetus and others, the placenta. PGD is performed by creating a small hole in the egg shell and removing a few cells representing the future placenta.. The cells are examined for the presence of genetic markers that are specific to the Y chromosome (the male chromosome). If these markers are present, the embryo is male. If the Y markers are not present, the embryo is female. An embryo transfer can then be scheduled with one or more embryos of the desired sex.
Couples may choose to use this technology for a number of reasons. For example, they may have several children of one sex and wish to balance their family with a child of the opposite sex. Or, they may be concerned about a genetic disease that tends to affect male children more than female children. The gender selection process can also be easily combined with further evaluation for chromosomal abnormalities that could cause a fatal defect in the developing embryo.
Preimplantation Genetic Diagnosis (PGD) is the only reliable method for selecting the gender of a child. Sperm sorting is sometimes used by couples in the hope of increasing the chances of conceiving a child of the desired sex. However, the effectiveness of this method is unproven lacking data from large, multicenter trials.
There have now been thousands of children born from embryos that underwent PGD. Testing of embryos on day 5 of development (blastocyst) is felt to be safest of all techniques. Transferring a normal embryo greatly reduces the chance carrying a fetus with a chromosomal abnormality such as Down’s Syndrome or other more lethal conditions.
Patients sometimes use gender selection if they already have children of one gender and wish to balance their family with a child of the opposite gender. Or, the family may have a history of genetic disorders that are passed down through the X chromosome. These recessive traits typically affect male children because they have only one X chromosome. Choosing to have a girl makes it unlikely that this disease will affect the child. Some patients simply prefer to have a child of a specific gender.
Some people feel that selection of non-essential characteristics like gender is not an appropriate use of medical technology. Others believe gender selection is an aspect of reproductive rights and parents should be allowed to make this decision. The use of this technology to prevent genetic disease or to provide family balancing is typically viewed as less controversial than other uses.