Going through an IVF cycle comes with a lot of questions and many things that are out of a couple’s control. But for all of the details that are out of a person’s hands, there are a few that they may actually have a say in.
For instance, if you're undergoing fertility treatments in the United States, you may have the option to select the gender of your baby. Gender selection, or family balancing, is possible as part of the in vitro fertilization (IVF) process.
IVF and Gender Selection
Couples may want to pursue gender selection for many reasons. In some cases, they may be interested in “family balancing” reasons. For example, they may have one or two girls and wish to have a son (or vice versa). In other cases, one or both partners may have a genetic condition in their family history that is tied to the sex of the baby. For example, conditions such as Klinefelter syndrome, Duchenne muscular dystrophy, and Hunter syndrome are typically linked to males.
Below, we’ll review how the gender of an embryo is determined during IVF, how gender selection works, and, most importantly, how it can help increase your chances of a successful IVF cycle and a healthy pregnancy.
A Quick Genetics Lesson
Your baby’s gender is determined primarily by the sperm’s chromosomes. A sperm cell can take either an X chromosome or a Y chromosome. However, women’s eggs only have an X chromosome. So, if you have a sperm carrying an X chromosome, and it meets and fertilizes eggs that also have an X chromosome, this will create a female or a baby girl.
We carry two copies of each chromosome, one inherited from each parent. Healthy embryos have 46 chromosomes, comprising 22 pairs of autosomal chromosomes and one pair of sex chromosomes (XX for females and XY for males). These healthy cells are called euploid.
When an embryo has extra or missing copies of a chromosome, it is called aneuploid — aneuploidy results in high rates of implantation failure and miscarriage or a baby born with a genetic syndrome.
Pre-Implantation Genetic Testing for Gender Selection
When undergoing IVF, you can discuss the option and benefits of genetic testing with your fertility doctor. There is Pre-implantation Genetic Testing for Aneuploidy (PGT-A) and Pre-implantation Genetic Testing for Monogenic (PGT-M).
With PGT-A, it can help determine which embryos you have to transfer that are considered chromosomally normal (euploid). PGT-M is a customized test that detects specific monogenic/single gene defects. It looks for specific inherited abnormalities found in conditions like Tay-Sachs, Cystic Fibrosis, Spinal Muscular Atrophy, Fragile X, etc., to help reduce the chances of your baby having them.
With both tests, you would go through the suggested IVF protocol your clinic is recommending, and once your embryos reach the “blastocyst stage,” an embryologist would remove a few cells from each. These cells would then be analyzed by looking at the number of chromosomes and the gender of these chromosomes within each embryo.
From there, your reproductive endocrinologist would discuss the findings with you and select which embryos to transfer. This means that you’ll be able to not only know the gender of your baby but also have an increased sense of confidence that the embryo(s) you are transferring has a higher chance of implantation in the uterine lining and a lower chance of miscarriage.
What About Sperm Sorting?
Prior to PGT, sperm sorting was used to increase the odds of having a specific gender. Sperm sorting, also known as “The Microsort Method” or “Ericsson Method,” entails separating sperm cells based on how much DNA each sperm cell contains. For example, the X chromosome has more DNA than the Y chromosome. It works by using a fluorescent dye that attaches to DNA. The theory is that the sperm with more DNA would glow brightly, indicating which chromosome it is (X or Y). They then separate the sperm based on these results, and the preferred gender would be used for intrauterine inseminations (IUI) or IVF.
While sperm sorting is less expensive, the results aren’t as reliable. When sperm sorting is used, there is a 60% - 70% chance of accuracy. With genetic testing, it’s around 98%. There have also been safety concerns about sperm sorting in general. This is why most clinics in the United States do not offer it to their patients.
Whatever your reason for being interested in gender selection, you should feel comfortable asking your doctor about it. For some, it may just be one of the biggest silver linings of IVF.
Jennifer “Jay” Palumbo is a freelance writer, infertility and women’s rights advocate, former stand-up comic, author of the blog, “The 2 Week Wait,” and proud IVF Mom. Her articles have been featured in Time magazine, Huffington Post, and ScaryMommy. She has been interviewed on news outlets such as CNN, NPR, and BBC, where she has demonstrated her ability to make even reproductive issues fun and educational. You can follow her "infertility humor" on Instagram at @jennjaypal.
