Gender Selection

Why do couples want to choose the gender of a baby?

These are two major reasons that couples may wish to pursue Gender Selection. The first is to prevent transmission of sex-linked genetic conditions, when a specific test for the condition is not available. This medically-based rationale is acceptable to most. However, most sex-linked diseases now have specific tests available which allow Preimplantation Genetic Diagnosis to avoid having a child affected with the disease itself, regardless of the child’s gender, rather than just attempting to avoid the disease based on gender of the offspring alone.

The second reason is a social one, to provide parents with a child of the preferred sex. We allow couples to specify sex and pursue “family balancing” after they have had at least one child of the opposite sex and have fully discussed with us the pros and cons as well as the risks and benefits of such an approach.

We do not recommend Gender Selection for a couple’s first pregnancy, but if you have one or more boys and would like to try for a girl (or the other way around) there is only one option currently available in the USA. All eggs are female – it is the man’s individual sperm which determine the gender of a baby.

MicroSort (no longer offered in the USA)

MicroSort, which is a method of separating sperm into X chromosome-bearing sperm (which result in female embryos) and Y-chromosome-bearing sperm (which result in male embryos), was not approved by the FDA and as such US patients are no longer eligible for treatment. The sorting is not perfect – about 70% chance of having a boy (and 30% chance of a girl) if you want a boy, and about 85% chance of having a girl (and 15% chance of a boy) if you want a girl.

Until recently the MicroSort technique for gender selection was only available for couples who have a genetic disorder which is gender-linked and it is not  for Family Balancing. It now appears that the MicroSort clinical trial was ended on March 31, 2012 and the FDA did not grant them leave to continue trials. This means that new patients will not be accepted for MicroSort.

In Vitro Fertilization with Preimplantation Genetic Diagnosis (IVF with PGD)

A more effective method of gender selection is still available at Overlake Reproductive Health – in vitro fertilization with Preimplantation Genetic Diagnosis (IVF with PGD). The woman undergoes in vitro Fertilization by taking injectable fertility medicines for around 8-10 days to stimulate her ovaries to make multiple eggs. The eggs are then removed using Transvaginal Aspiration (TVA), a short procedure performed in-office under an intravenous anesthetic. The same day, the male partner gives us a sperm sample which we use to fertilize the eggs, either using conventional IVF, mixing eggs and sperm together in a dish, for men with normal sperm counts, or ICSI (Intracytoplasmic Sperm Injection), injecting 1 sperm into each egg if the sperm is abnormal.

The fertilized eggs grow into embryos. On the third day of development, a skilled embryologist performs an embryo biopsy on each embryo with four cells or more. A very fine laser is used to make a hole in the outer covering of the embryo, then 1 cell is gently removed. This cell is sent to a genetic testing lab, where we can either test the gender of the embryo only (X and Y chromosome testing), or lok at all 24 chromosomes to pick up disorders like Down’s Syndrome (Trisomy 21) as well as determining gender. This process is called Preimplantation Genetic Diagnosis or PGD. The embryos are kept in the lab until the blastocyst stage (5 to 6 days of development). We use the PGD results to select the embryos to transfer back into the woman’s uterus. Any ‘extra’ embryos beyond the number we are willing to transfer ‘fresh’ can be cryopreserved (frozen) for later pregnancy attempts.

The gender testing is over 99% accurate, however we cannot guarantee that you will have good-quality embryos of the desired gender as it is determined by the sperm, and with MicroSort being unavailable the sperm should be close to 50% ‘male’ and 50% ‘female’.

Next Steps

If you are interested in Family Balancing or gender selection, please contact us to schedule your initial consultation with one of our MDs. We will recommend individualized testing to make sure that you have an acceptable chance of success before proceeding with treatment.

Additional Resources

For more detailed information on PGD, including success rates.