Gender selection refers to the determination of the desired gender prior to implantation of the embryo. The odds of having a boy or a girl are almost 50/50 in a natural conception cycle and dependent on the sperm. The egg has 22 chromosomes plus the X chromosome, and the sperm brings another 22 chromosomes with either an X or a Y chromosome. If the sperm that fertilizes the egg has a Y chromosome, the end result is a boy and a girl if sperm contains the X chromosome.
Historically, gender selection was offered to patients with genetic diseases that are more common in one gender versus the other. X-linked disorders refer to diseases that are gender specific and can be limited with the process of gender selection. Family balancing on the other hand is a more recent and relatively common request for gender selection and rarely a person may request a specific gender without any medical necessity. Such cases have been challenging for fertility practices and there is still controversy in honoring such an elective request.
There are currently two options for gender selection and the first option is to identify and isolate the sperm that would result in the desired gender, and use the selected sperm to fertilize the egg (Sperm Sorting - Microsort). Alternatively, eggs can be fertilized with unselected sperm and the embryos can be tested genetically for the desired gender (Preimplantation Genetic Diagnosis – PGD).
Microsort technology allows the sperm to be sorted based on the presence of X or Y chromosomes with approximately 60-80% accuracy. Any given sperm sample contains an even (50/50) amount of X (female) and Y (male) bearing sperm. MicroSort uses a machine called a flow cytometer to sort sperm su