Gender selection is an interesting and controversial topic in the field of reproductive medicine.
In this post, you’ll learn:
- How gender selection is possible with in vitro fertilization
- The process, methods, and success rates of gender selection protocols
- The pros and cons of the procedures
Let’s get started.
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Is gender selection possible in IVF?
Gender selection is possible through IVF and preimplantation genetic testing, a procedure that can determine the chromosomal makeup of an embryo.
It is essential to understand that the IVF process does not modify or change the sex of the embryos. IVF with preimplantation genetic testing simply allows us to know the sex of an embryo before implantation.
In other words, you cannot pick the gender of your baby, you can only transfer what you have available.
If you only make two embryos, and both are males, you only have male embryos to transfer.
Is gender selection legal?
In the United States, there are no state laws to prohibit the practice of IVF for gender selection.
With that said, gender selection is a topic of ethical concern, as depicted by this committee opinion by the American Society for Reproductive Medicine.
As a result, some fertility clinics may not allow you to do preimplantation genetic testing without medical reasons.
How do you determine the gender of an embryo?
The gender selection process requires several steps:
- Controlled ovarian stimulation with daily gonadotropin injections
- An egg retrieval (anesthesia procedure)
- Fertilization of your eggs with the desired sperm
- Allowing the fertilized eggs to grow and develop in the IVF laboratory for 5-7 days
- Biopsying any resulting embryos that make it to the blastocyst stage
- Freezing the embryos while you await the results of the biopsy
- Thawing and transferring the chosen embryo back into your uterus at a later time.
Of note, the embryo biopsy is meant to screen for chromosomal genetic disorders (like Down syndrome).
It just so happens that this test can also determine the gender of the embryo by looking at the sex chromosomes. Two X chromosomes indicate female (XX), and one X and one Y chromosome indicate a male (XY).
How accurate is gender selection in IVF?
With the latest technology, we can achieve ~99% accuracy in determining gender for embryos.
What are the risks of IVF gender selection?
For most couples who choose to undergo gender selection with IVF, the procedure is very safe and effective. However, all medical procedures do have some risks.
The risks of the procedure are related to the biopsy itself and the results it can provide.
Let’s go over these in more detail.
The Biopsy Procedure
This is particularly true because the biopsy is taken from the trophectoderm, which are the cells that will become the placenta and not the embryo.
However, there does appear to be an increased risk of conditions that increase your blood pressure in pregnancy, which seem to originate from the placenta.
While these data are reassuring, we cannot conclusively say that embryo biopsy has no long-term effects.
There simply hasn’t been enough time or studies to know for certain.
I go over more details in my post on The Embryo Biopsy: Risks, Benefits, & Alternatives.
The Results of The Biopsy
The second risk of gender selection relates to the results of the biopsy.
Remember, this procedure is designed to look for genetic abnormalities in the embryo.
Errors in the interpretation of the genetic results can occur, especially since we are only biopsying the trophectoderm cells and not the cells that will make the embryo. False positives and false negatives are reported to be approximately 4%.
As a result, there is a slight chance that you may get an abnormal genetic result, despite the embryo being the gender you desire.
Freezing and Warming of The Embryos
Lastly, there is a small risk that an embryo will not survive the warming (aka thawing) process after it is frozen.
Thankfully, over >90% of embryos will survive a freeze/thaw cycle.
IVF gender selection pros and cons
Next, let’s go over some pros and cons of knowing the gender of an embryo before you transfer it.
Pros of Gender Selection
- Family balancing
- Decreased risk of passing on an X-linked genetic disorder
Knowing the gender of your embryo can be helpful if you desire to have a son or a daughter and in a specific order.
While there is no medical reason to choose one sex over another, many parents strongly prefer one gender to balance their family for personal reasons.
Decreased risk of passing on an X-linked genetic disorder
Secondly, knowing the gender of your embryo is helpful if you are at risk of passing an X-linked genetic disorder.
These gender-specific genetic abnormalities tend to affect males more aggressively (or exclusively). Common examples include:
- Duchenne’s muscular dystrophy
- Hemophilia A and Hemophilia B
- Fragile X syndrome
- Red-green color blindness
As such, you can choose to transfer a female embryo (if available) to decrease your risk of having a child with the disorder.
Cons of Gender Selection
- Discovering that you may not be able to use the embryos you want (due to a chromosomal abnormality)
- Disappointment if your embryo is not the gender you desire
- Decision over what to do with unwanted or unused embryos
- Gender bias
- Requires embryo biopsy
- Additional costs
- Delays pregnancy a bit as you await the results
Disappointment in results
Don’t forget, the gender of the embryo is already determined. After a PGT biopsy, it is possible not to have any embryos of your desired sex, or the embryo that is the preferred sex is chromosomally abnormal.
The image below shows a genetic biopsy result of a male embryo (XY) but with a genetic abnormality (three copies of chromosome 21).
If you happen to make one or more embryos of the undesired sex, you will have to decide what you would like to do with them, which can be an ethical issue.
Options include: using the embryos, discarding the embryos, anonymous donation to another couple, or donation for research.
Since the advent of PGT, it appears that PGT is skewing the natural sex ratio towards male children.
Gender selection may be inadvertently devaluing perfectly healthy female embryos.
Embryo Biopsy Risks
In general, the embryo biopsy is considered a fairly safe procedure. But at this time, there isn’t enough data to conclusively say that there are no long-term impacts to the biopsy and embryo freezing.
Lastly, PGT will add significant costs to your IVF cycle. On top of the biopsy and the interpretation of those results, you will also need to undergo a frozen embryo transfer cycle.
All of which will add time and costs to the process.
With that said, you will likely need to freeze embryos anyway if you have generated more than one embryo suitable for transfer.
How much does gender selection with IVF cost?
The cost of biopsying your embryos and analyzing the genetic information may add an additional $3000-5000 on top of the IVF treatment cycle (which can be $15,000-$20,000).
In addition, you will then need to undergo a frozen embryo transfer cycle (in which the frozen embryos are warmed and then transferred back into your uterus). Depending on your fertility clinic and insurance coverage, this may cost you an additional $5000 or more as well.
Every clinic is different. Be sure to speak with your healthcare providers to learn what your particular costs may be.
Other Related Questions
Are IVF babies more likely to be boys or girls?
Interestingly, studies show that you are more likely to have a boy (52-55%) if you do an IVF cycle with conventional insemination (i.e. putting the egg together in a dish with sperm).
On the other hand, some studies show that ICSI cycles (intracytoplasmic sperm injection- where a single sperm is injected directly into the egg) are more likely to yield a female.
Can you guarantee a boy with IVF?
Unfortunately, there is no way to guarantee a baby of a particular gender using IVF and PGT.
Even if you are willing to undergo the embryo biopsy only to determine the gender, there is still a ~50% chance of getting an embryo of the desired gender.
How common is gender selection?
There is no data to know how often people do IVF simply for the sole purpose of gender selection.
Many IVF patients will do PGT-A to avoid transferring an embryo with chromosomal abnormalities and elect to know the gender of the embryos as a by-product.
What is the most reliable method of gender selection?
The most reliable method of gender selection is IVF with preimplantation genetic testing. Success rates of determining the gender are close to 100%.
There is another method known as sperm sorting- in which a device can separate sperm that contain the X chromosome and sperm that have the Y chromosome. As such, you can use only sperm with the desired sex chromosome.
This technology is NOT widely available, as its only purpose is manipulating sperm for a preferred gender.
Can you tell if an embryo is a boy or girl?
The only way to determine the gender of an embryo is through PGT.
There are no discernable features of a blastocyst embryo that tell you if it is a boy or a girl.
Final Words on Sex Selection
While controversial with many ethical implications, gender selection with assisted reproductive technology is made possible through the use of preimplantation genetic testing.
It works by determining the chromosomal makeup of the embryo(s) you generated during an IVF cycle. IVF does not change or alter the gender of your embryo.
By knowing the chromosomal makeup of the embryo, you can choose to only transfer embryos of the desired sex (assuming it is also chromosomally normal).
Alex Robles, MD
Alex Robles is a Spanish-speaking Latino-American Reproductive Endocrinologist and Infertility specialist in New York City, and board-certified OBGYN in his final year of fellowship at Columbia University Medical College. He has a special interest in exercise, lifestyle, & nutrition.
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