Gender selection — choosing the sex of your baby — is a a topic that inspires much discussion centered around moral concerns, ethical concerns and religion. But in my experience, parents who want to choose the sex of their baby are doing it for medical reasons (to avoid passing on a sex-linked genetic disease) or for family balancing (for example, they have two boys and want that little girl to complete their family).
In addition, there are many couples who are already undergoing in vitro fertilization (IVF) and having genetic testing on the embryos to check for chromosomal abnormalities. These tests make it very simple to go ahead and select the embryo of the desired sex to transfer to the woman’s uterus when the time comes.
Recent news articles talk about how baby gender selection is banned in Britain, thus many couples are traveling to the United States for the procedure. British law only allows gender testing where there is a family history of serious physical or mental medical conditions that are gender related. In my Chicago fertility practice, we know couples have many reasons for choosing whether they have a boy or girl — and we welcome couples from all over the world who are working to build their families.
How does sex selection work? It’s helpful to understand some basic biology. The gender of a child is decided by the sex chromosome carried by the sperm, because sperm carry both X and Y chromosomes, while eggs only have X. When an X-bearing sperm fertilizes the X-bearing egg, you have a female embryo. When a Y-bearing sperm fertilizes the X-bearing egg, you have a male. With natural conception, you have a 50 percent chance of conceiving a boy and a 50 percent chance of conceiving a girl.
There are sperm separation methods that may increase your chances of having one sex or the other. The traditional sperm sorting method is called the Ericsson method, and it safely separates sperm in the lab to allow the majority of the sperm capable of producing the desired gender to be recovered and utilized for intrauterine insemination (IUI) or in vitro fertilization (IVF). However, the success rate of this method is only 60 to 75 percent, and the simple fact is that most of these methods don't work well, and we have stopped using these techniques. A newer sperm sorting method called Microsort was more successful, but it did not receive Food and Drug Administration approval and is therefore no longer available in the United States as of March 2012.
Preimplantation genetic screening (PGS) — also called preimplantation genetic diagnosis (PGD) — is the most accurate way (99.9 percent accurate) to select the gender of your baby. PGS must be done with IVF. The procedure entails ovarian stimulation, egg retrieval and fertilization in the lab. Then:
- A cell or cells are removed from the embryo on Day 5 when the embryo is a blastocyst. The portion of the cells becoming the fetus is not biopsied — only the cells that are becoming the placenta. This is a marked improvement in accuracy, safety and pregnancy rates
- Using Comparative Genomic Hybridization (CGH) technology all 23 chromosome pairs can be screened by genetic specialists. This screening can determine the sex, as well as find any abnormal chromosomes (aneuploidy), such as trisomy 21 (Down Syndrome).
- The genetically normal embryo or embryos of the desired gender are transferred to the mother’s uterus the next day — or they can be frozen (vitrified) and transferred at a future date, months or years later.
The success rates for IVF with gender selection are very similar to the rates of IVF without gender selection. Gender selection is a safe method that will help you build the family you desire.