Reframing Sex Selection in IVF

Sex selection has become a popular topic amongst couples desiring children. Families seek sex selection for many reasons, including family balance and wanting to ensure that their child is healthy. At Arizona Center for Reproductive Endocrinology and Infertility, we offer sex selection services through PGD and PGS.

Preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS) are types of genetic testing that can be performed on embryos before implantation.

In this article, we want to open up a discussion about sex selection and dispel some of the myths that surround it. We’ll also give a more in-depth explanation of PGS and PGD and how sex selection factors into those procedures.

The history of the sex selection process

The first baby conceived through in vitro fertilization (IVF) was born in 1978. Eleven years later, in 1989, embryologist and geneticist Alan Handyside pioneered the development of preimplantation genetic diagnosis (PGD).

Handyside used PGD to screen embryos for cystic fibrosis, a disease linked to the X chromosome. His work quickly led to tests for many more conditions, including hemophilia and sickle cell anemia.

Early PGD science naturally intertwined with sex selection. For example, X-linked diseases affect males more often. Parents could choose to implant only female embryos to prevent having a child with one of these diseases.

However, this is no longer necessary. Science has evolved such that doctors can now distinguish between embryos that carry the mutation and those that will be affected by the disease. 

The first baby conceived through PGD was born in 1990.

In the 2000s, multiple important sex selection breakthroughs occurred. Scientists discovered how to extract additional cells during the biopsy, allowing for more nuanced genetic testing. In addition, Array comparative genomic hybridization (aCGH) became available. This is a high-resolution chromosomal test that can quickly and accurately assess embryos.

Preimplantation genetic screening (PGS) was developed soon after aCGH. PGS screens embryos for aneuploidy, or abnormal chromosome number. Aneuploid embryos are associated with pregnancy loss and birth defects.

PGS quickly became the preferred method of sex selection because it improves implantation rates and reduces the risk of miscarriage.

How PGD and PGS work

Sex selection with PGD or PGS is performed as part of an IVF cycle.

During IVF, eggs are retrieved from the ovaries and fertilized with sperm in a laboratory.

Embryos develop for a few days before they are biopsied, and the doctor removes one or more cells. The cells are then tested for chromosomal abnormalities or the presence of a specific genetic disease.

Healthy embryos are transferred to the uterus. 

PGS can be performed on all embryos, allowing couples to choose the best embryo for implantation regardless of sex.

PGD is only performed on embryos with suspected genetic diseases. These diseases could affect only males, such as hemophilia, or one that affects both sexes, such as Huntington’s disease.

Sex selection is possible with both options. However, choosing traits like hair color, eye color, or intelligence is not currently possible. 

How PGD and PGS in sex selection help create more balanced families

Sex selection in IVF can improve implantation rates.

It can also help families avoid the heartache of miscarrying an aneuploid baby or giving birth to a child with a serious genetic disease.

That’s because PGD and PGS are not just used for sex selection. These tests screen embryos for a wide range of genetic diseases. We help ensure that only the healthiest embryos are transferred to the uterus by testing embryos before implantation.

For example, let’s say a couple has a family history of hemophilia. They could use PGD to test their embryos for the disease. Only unaffected embryos would be transferred, eliminating the chance of having a child with hemophilia.

PGD and PGS also allow families to balance the number of boys and girls in their family. Many couples seek sex selection because they have a child with a serious, chronic illness or they have had multiple miscarriages.

It’s impossible to predict everything that may happen, but PGD and PGS procedures give families the best chance for a healthy baby.

Who is PGD and PGS recommended for

PGD and PGS can help couples have successful pregnancies.

PGS is appropriate for parents with no known genetic abnormalities. As we explained above, PGS looks for aneuploidy or abnormal chromosomes. The affected embryos are unlikely to implant. If they do, the pregnancy will often end in a miscarriage.

Chromosome abnormalities become significantly more likely as a female ages. When that female is over 35, 50% or more of their eggs may be abnormal. That number jumps even higher when a female enters their 40s and 50s. That’s why PGS is recommended when a female is 35 and older.

However, other couples can benefit from PGS as well. The process is very helpful for couples who have experienced miscarriages or failed IVF rounds in the past.

PGS is also recommended for couples who want to balance their families through sex selection. At Arizona Center for Reproductive Endocrinology and Infertility, couples can simply come to the clinic and choose the sex they prefer.

Ultimately, any parent undergoing IVF can choose PGS. PGD, however, is only recommended when a couple has a known genetic disease in their family. By testing embryos, doctors can help ensure that only the highest quality embryos are transferred to the uterus.

What are the risks of PGD and PGS

Potential risks associated with PGD and PGS include:

  • Low egg count: If a female has a low egg count, the doctor may not be able to harvest enough healthy eggs for successful testing. That limits their options for treatment.
  • Mosaicism: Mosaicism occurs when some of the cells in an embryo have the correct number of chromosomes, but other cells don’t. Mosaicism isn’t always detected during a biopsy, which means it’s possible to transfer an embryo that appears healthy but isn’t.

    Or, the opposite may happen. A seemingly poor-quality embryo may be discarded when the problem would have corrected itself.

  • Incorrect Results: In very rare cases, the results of the biopsy may be incorrect. You might receive a false positive or a false negative.
  • Damage to the Embryo: The biopsy itself may damage the embryo. This is a very small risk, however – less than 1%.

Your fertility doctor knows to weigh these slight risks against the multiple advantages of PGD and PGS. 

Conclusion

PGD and PGS are two procedures that can be performed during IVF. They’re both used to screen embryos for genetic abnormalities.

PGS is an option for all parents undergoing IVF, while PGD is for couples testing for a specific genetic disease.

Both procedures have a few potential risks, but the success rates are promising.

If you’re interested in learning more about PGD or PGS, please contact Arizona Center for Reproductive Endocrinology and Infertility today. We’ll be happy to answer any of your questions. Our team can help you decide if either of these procedures is the right choice for your family. Call the number at 520-326-0001 and follow us on Instagram.


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