Gender Selection
Determining a baby’s gender in advance is possible with today’s technology.
This approach includes several methods that couples may choose in order to select gender beforehand. These include Preimplantation Genetic Testing (PGT) and other gender selection techniques.
The topic of selecting a baby’s gender has been debated in Western societies for a long time. Although it is prohibited in many countries, it is legally available in countries such as the United States, Canada, and the Turkish Republic of Northern Cyprus (TRNC).
These genetic tests performed on embryos have been increasingly used since the early 2000s.
Concerns that gender selection will shift the world population in favor of males are unfounded. In practice, families most often want a child of a different gender from the children they already have. Since many families already have children of both genders, this procedure does not concern them. Some are already satisfied with their current situation.
Only a small portion of families with, for example, two daughters or two sons choose to go through this process in order to have a child of the opposite gender.
In that sense, this procedure can be described as “family balancing”, meaning balancing the genders of children within the family.
What Is Family Balancing?
Family balancing is a type of IVF treatment that enables couples to choose the gender of their future child. It can be performed using techniques such as Preimplantation Genetic Testing (PGT) or sperm selection.
What Is the Purpose of Family Balancing?
Family balancing allows couples to have a child of the desired gender and may help maintain a balance within the family. For example, if a family has only girls or only boys, family balancing may help them have a child of the other gender.
How Is Family Balancing Performed?
Family balancing is carried out using methods such as PGT or sperm selection, which make it possible to select an embryo of the desired gender. However, because this technology can raise ethical concerns, it is prohibited or restricted in some countries.
For this reason, couples are advised to review the legal regulations and guidelines in their own country and consult a specialist.
Family balancing is also referred to as gender selection, gender selection in reproduction, reproductive technology with gender selection, and reproductive medicine with gender selection.
What Is Gender Selection?
Gender selection is the process of determining the baby’s gender before pregnancy. Today, this is performed through genetic testing on embryos. While it is legal in some countries, it is prohibited in others.
Key Points You Should Know
Gender selection is an IVF-based method that allows couples to choose the gender of their child.
It is performed using techniques such as PGT or sperm selection.
It may help families achieve a gender balance.
The technology is prohibited or restricted in some countries.
Couples should research local regulations and consult a specialist for further guidance.
Gender Selection Methods
There are two main methods used for gender selection:
Sperm sorting (sperm separation):
This method attempts to separate sperm based on the chromosomes that determine gender, allowing sperm with the desired sex chromosome to be used.Embryo selection:
During IVF treatment, embryos are created and tested, and an embryo of the desired gender is selected for transfer.
Gender Selection and Family Balancing
Gender selection is considered ethically unacceptable by some groups. While concerns exist that it could change population balance, when performed based on family preference, it is often described as family balancing—balancing the genders of children within a family. These debates usually relate to families who want a child of a different gender.
Thanks to modern technology, gender selection has become possible. When carried out based on family preference (family balancing), it does not lead to societal gender imbalance.
What Is Gender Determination?
Gender determination is the process of identifying a baby’s gender in advance. Today, it is performed on embryos using genetic testing.
It is used as part of IVF treatment and may be performed through PGT (Preimplantation Genetic Testing) or techniques such as sperm selection.
Gender determination may help couples have a child of the desired gender and preserve gender balance in the family. However, this technology is prohibited or restricted in some countries.
Couples seeking more information should research legal regulations in their own country and consult a specialist.
As mentioned, there are two methods: sperm sorting and embryo selection.
The Gender Determination Process: 5 Stages
Gender determination typically consists of five stages:
1) Pre-treatment Evaluation and Preparation
An initial consultation is required. Careful evaluation of patients is important.
During this first visit, the necessary examinations are performed for the evaluation of the prospective mother. Missing tests are planned. This first consultation is extremely important for achieving successful outcomes.
A) Ultrasound Evaluation of the Prospective Mother
For optimal evaluation, it is recommended that the woman is between days 14–26 of her menstrual cycle. Examinations performed immediately after menstruation may not provide sufficient information. Fibroids, uterine abnormalities, and polyps can be detected by ultrasound.
1) Measuring and evaluating endometrial thickness
The endometrium reaches its maximum thickness around days 12–14 of the cycle and remains relatively stable afterward. If there is an ovulation-related problem, this may affect the endometrium.
A healthy endometrium is typically over 8 mm and appears as three parallel lines (“triple line”).
Irregularities within these lines—such as polyps, fibroids, or fluid accumulation—may create problems. (Fluid is not expected in a normal endometrium and may indicate adhesions, often after cesarean section or surgery.)
Black spot-like structures within the endometrium are called adenomyosis. Adenomyosis does not reduce the chance of pregnancy.
In women who menstruate normally or receive adequate medication to menstruate, the endometrium is expected to be above 8 mm between days 14–26. Any intrauterine intervention or surgery may damage the uterine lining. This damage may lead to reduced menstrual flow and should be detected and managed appropriately.
2) Determining ovulation capacity (egg reserve) for gender selection
Small cyst-like structures called antral follicles are evaluated and counted in the ovaries. Counting antral follicles is the most appropriate method to assess egg reserve.
Hormone tests such as FSH and AMH may assist less experienced physicians, but an experienced IVF specialist does not base evaluation solely on these results. In particular, the FSH test may be misleading.
After evaluating ovarian reserve, patients are informed about their likelihood of pregnancy. Suitable couples begin treatment and individualized protocols are selected according to egg production capacity. Patients do not need to stay at our center throughout treatment; it can be continued in their home country with monitoring.
For gender selection, the number of eggs that may be sufficient for standard IVF may not be enough. To achieve a healthy outcome, the patient should have the capacity to produce at least 10 mature eggs.
A commonly used technique known as the “pooling method” (collecting eggs repeatedly) is not considered appropriate. If AMH is low, even collecting 20 eggs may unfortunately lead to disappointing results.
Medication can help retrieve existing eggs, but there is no medication that can increase the number of eggs that do not exist.
For women with AMH below 0.5, we recommend using donor eggs. Performing the procedure with the patient’s own eggs in such cases is unfair due to the very low chance of success. Even when pregnancy occurs, it often does not continue healthily and may be lost early.
B) HSG (Hysterosalpingography / Dye Test)
1) Evaluation of the fallopian tubes
A special device is placed at the entrance of the uterus and contrast material is administered for imaging. This is the most definitive method for detecting tubal problems.
Tubal swelling negatively affects IVF results. Hydrosalpinx (fluid in the tube) may cause the embryo to die due to contact with harmful fluid. HSG is an essential test in infertility evaluation, and studies show alternative tests do not match HSG in accuracy.
An HSG is generally valid for two years. If a patient undergoes surgery, HSG should be repeated because postoperative adhesions may lead to IVF failure. In certain special cases, it may not be required.
We believe mild anesthesia is beneficial for HSG. Patients should avoid eating or drinking for 5–6 hours before anesthesia. If the stomach is not empty, aspirated contents can cause serious harm. If anything has been eaten or drunk, the anesthesiologist must be informed so the anesthesia plan can be adjusted.
When performed correctly with adequate pressure, HSG can be painful because pain may occur as contrast passes through the tubes.
2) Uterine cavity assessment
Conditions such as polyps, fibroids, and adhesions can be identified. HSG is one of the easiest tools for diagnosing adhesions. Adhesions can also be diagnosed via hysteroscopy, but this is more expensive and is performed in an operating room.
Identified problems are treated. In severe adhesions (Asherman syndrome), there may be limited options beyond surrogacy.
3) Review of medications and chronic diseases
Risk-related conditions and medications are assessed and precautions are taken. Blood thinners and diabetes medications are particularly important. Some may need to be stopped or replaced. Patients must inform their doctor about all medications they use.
D) Additional Blood Tests
Complete blood count
Bleeding and clotting tests
Thyroid tests
Infectious disease screening
Additional tests depending on the patient’s specific condition
Risks of the Procedure
Determining gender with PGD/PGT does not create a serious additional risk for women beyond the risks of IVF itself. The risk of OHSS (ovarian hyperstimulation syndrome) should be assessed and prevented. OHSS is a dangerous condition that can cause fluid accumulation in the abdomen and chest, and in rare cases even the brain. However, in the last 6–7 years and among thousands of patients, none of our patients have experienced this condition.
Today, OHSS is considered a sign of inadequate clinical practice. In the United States, OHSS may be regarded as a medical error. Chronic diseases and obesity can create complications and also reduce pregnancy chances. Patients with such risks must be evaluated carefully.
In addition to OHSS, there are anesthesia and surgical risks. Therefore, patients should choose their doctor and clinic carefully.
E) Evaluation of the Male Partner
This is simpler and faster compared to evaluation of the female partner. The main requirement is semen analysis. If there is a sperm issue, advanced tests may include surgical sperm retrieval and genetic testing.
In situations such as diabetes, stress, or inability to provide a sample, sperm may also be obtained by injection.
Preparation is made accordingly for egg retrieval day. Patients who need anesthesia are informed in advance about precautions.
Blood tests are usually performed. The stomach must be empty before anesthesia, therefore eating and drinking are prohibited for 5–6 hours. Patients undergoing surgery are asked about medications. Blood thinners such as coumarin and aspirin are adjusted. If anemia is present, precautions are taken.
Except in rare cases, medication is not necessary for men.
Medications given to increase sperm count, motility, or morphology generally do not provide benefit. If bacteria or white blood cells (leukocytes) are detected in semen, antibiotic treatment may be given.
F) Completion of Genetic and Hematological Tests for Both Partners
Some tests may take up to 30 days to be completed.
Couples with a family history of genetic diseases should be prepared for additional tests that may require 30–45 days. Mutation tests for conditions such as thalassemia may also take time.
The AMH test typically takes around two weeks.
2) Medication Phase
After the initial consultation and completion of missing tests, the second stage is the medication phase.
The ovaries are stimulated with medication to promote egg development. Obtaining an adequate number of eggs is one of the most important skills of an IVF specialist.
Treatment generally begins on the second or third day of the menstrual cycle. In special cases, treatment may also start on day 21.
Patients can use these medications at home. The injections are as thin as insulin needles and are administered subcutaneously into the abdominal area. Ultrasound monitoring is required on certain days. Approximately 2–3 ultrasound scans are performed to examine and measure follicles in the ovaries.
Eggs are not directly visible on ultrasound; they are located within sacs called follicles.
Medication is typically considered in two parts:
First, follicles are grown up to 14 mm
Second, early ovulation is prevented
When follicles reach the desired size (about 20 mm), an HCG “trigger shot” is administered to allow egg collection. If more than 15–16 follicles develop, a special triggering method is used to prevent OHSS.
In such cases, embryos are frozen and stored for transfer in later months.
3) Egg Retrieval and ICSI (Microinjection)
Approximately 35–36 hours after the HCG injection, egg retrieval is performed under anesthesia. On the same day, the retrieved eggs are fertilized using the male partner’s sperm via ICSI.
Egg retrieval (OPU—oocyte pick-up) is performed under anesthesia and takes about 15 minutes, with an anesthesiologist present. Follicular fluid is aspirated and eggs are searched for under a microscope.
The eggs are kept in the laboratory under appropriate conditions for 60–90 minutes and then the outer layer is removed using an enzyme and mechanical techniques.
At this stage, identifying eggs that are suitable for fertilization (MII eggs) is crucial. The number of MII eggs is more important than the total number retrieved.
Prepared sperm are injected into the eggs using a micromanipulator. The fertilized eggs are incubated for 16–18 hours. Successfully fertilized eggs are identified as 2PN.
Embryos are then cultured for a further 48 hours in a controlled environment.
4) Embryo Biopsy and Genetic Testing
Between 3 to 5 days after fertilization, a biopsy (cell sampling) is performed on suitable embryos.
Day 3 biopsy: From embryos with 6–8 cells, typically 1–2 cells are removed (blastomeres).
Day 5 biopsy (blastocyst stage): Cells are removed from the outer layer (trophectoderm) using a laser to create an opening or to separate a portion of the outer cells.
The collected samples are prepared for genetic analysis and sent to the genetic laboratory.
We avoid day 3 biopsy unless necessary because the results are less reliable. Abnormal areas within an embryo may be corrected naturally during development; therefore, day 5 biopsy is considered more reliable.
Day 5 Blastocyst Biopsy (Trophectoderm Biopsy)
With this technique, after laser biopsy of day 5 blastocysts, our clinic uses a rapid genetic determination test that provides results within two hours.
Patients do not need to wait for the next menstrual cycle for transfer. Healthy embryos identified through genetic analysis are transferred to the uterus.
Genetics has advanced faster than IVF. Therefore, maintaining a laboratory capable of every genetic test is not economically feasible. With years of experience, we collaborate with internationally recognized genetic centers when needed.
In rare cases, even diseases that may take years to identify have been detected in our clinic. For families seeking extensive carrier screening, the Carrier Map™ test can screen 191 diseases, 1,479 mutations, and 180 genetic disorders.
These tests are performed on the parents and are quite expensive.
Genetic Testing Methods Used
Genetic testing is performed in three main ways:
a) FISH (Fluorescent In Situ Hybridization)
This is the most practical method among the three. Using ready-made kits, the nucleus is stained and examined under a fluorescent microscope. Typically, chromosomes X, Y, 21, 18, and 13 are analyzed. Up to 9 chromosomes can be evaluated. This method requires significant expertise, as faint or stained markings may lead to incorrect diagnosis.
We primarily use this method for gender determination because it provides fast results at a reasonable cost. Results are also assessed with computer technology.
b) PCR (Polymerase Chain Reaction)
This method can be used to test single-gene disorders such as thalassemia. It is highly suitable for screening genetic disorders like thalassemia (Mediterranean anemia) and hemophilia.
During testing, strict precautions are required to prevent contamination from other DNA sources. Mutations in the mother and father must be identified in advance.
PCR is more expensive than FISH. We prefer this method when gender determination is performed for patients with known gene mutations.
c) Preimplantation Genetic Screening (PGS) / Array-CGH
Chromosomal abnormalities are believed to be a major factor in reduced pregnancy rates and the high miscarriage rates seen in assisted reproduction.
PGS aims to identify embryos that are more likely to be chromosomally normal (euploid) and suitable for transfer. It is designed to improve live birth rates, especially for women with recurrent implantation failure, recurrent pregnancy loss, or advanced maternal age.
Array Comparative Genomic Hybridization (Array-CGH) has been proposed to overcome technical challenges and provides the best available genetic screening, allowing assessment of all chromosomes. It is performed through our partner laboratory in the United States and enables evaluation of 46 chromosomes, with results typically available in 24–30 hours.
Array-CGH can be used simultaneously for translocations, inversions, and other chromosomal anomalies. The data are clear, precise, and reliable. Chromosome analysis can be performed alone or combined with mutation comparison on the same sample.
NGS (Next Generation Sequencing)
NGS is the most advanced genetic diagnostic method currently used. It can screen approximately 20,000 genes and is the most appropriate method for diagnosing known hereditary diseases in embryos.
It is not used to determine gender. Its disadvantages are high cost and a waiting period of approximately 20 days.
5) Embryo Transfer and Embryo Freezing
Based on genetic laboratory results, healthy embryos of the desired gender are selected and transferred to the prospective mother. If there are more embryos than needed, remaining embryos can be frozen for future use.
Some of our patients have become pregnant again by using these frozen embryos later.
Advantages of Genetic Analysis
Enables having a child of the desired gender and, if requested, genetic screening as well—helping prevent many genetic disorders.
Provides a higher pregnancy chance compared to other techniques.
Increases the probability of obtaining the desired gender.
Can be used in families at risk for sex-linked diseases and in couples who wish to plan their family.
Other methods besides sperm sorting and genetic analysis have been attempted, but their results remain questionable. Due to lower success rates and lack of strong scientific basis, these methods are used far less and their reliability is debated.
Other Methods (Less Reliable)
MicroSort
A technique aiming to separate X- and Y-bearing sperm using a specialized device. Sperm are separated based on electrical charge (gradient), then used via IUI or IVF-ICSI.
Reported success rates:
92% for girls
81% for boys
However, due to concerns about reliability and a margin of error, it is not widely preferred. It is also costly. The company that developed it (based in the U.S.) reportedly had its FDA approval revoked.
Shettles Method
A timing method based on theories about speed and durability differences between X- and Y-bearing sperm.
For a girl: intercourse is recommended 2–4 days before ovulation
For a boy: intercourse is recommended 1 day before ovulation
Assuming hundreds of millions of sperm behave in such a controlled pattern is unrealistic. The claim that Y-bearing sperm die earlier and are less durable has not been scientifically proven.
Diagnosis After Pregnancy Has Occurred (CVS)
One of the best-known methods is CVS (Chorionic Villus Sampling). It involves taking a small sample of chorionic villi (which later form the placenta) at 9–11 weeks of pregnancy. It was developed for early diagnosis of certain diseases and can also be used for early gender determination. It supports diagnosis of Down syndrome and other common conditions.
A method based on maternal blood testing is still experimental and its ethical aspects are debated.
Another approach based on washing sperm with a special albumin-containing fluid has not been scientifically proven. Its success in selecting gender is claimed to be around 70%, but the underlying assumptions are not confirmed.
Chinese Calendar / Ericsson Albumin Method
The so-called Chinese calendar claims there is a relationship between the mother’s age and the month of conception in predicting the baby’s gender.
This method has no scientific basis and does not change the natural 50% probability. Although about 50% of users may “succeed,” the other 50% will be disappointed. Couples should not rely on this method.
Conditions for Success
Gender selection through embryo studies is defined as “gender determination” or “gender determination with PGD/PGT.” Since separating sperm reliably is not possible, genetic analysis performed before embryo transfer is the only definitive method for gender determination, and it provides the highest success.
Because of this, approximately 99% of all gender selection procedures are performed through genetic diagnosis based on embryo testing.
To achieve near-100% accurate results with embryo-based genetic testing, several points must be considered:
1) The woman’s ovulation capacity (egg reserve)
Egg reserve, age, and number of previous births are highly important. Without enough eggs, pregnancy may not be possible.
Reproductive age may be estimated by subtracting the number of full-term births from the woman’s chronological age (e.g., a 45-year-old woman with 6 births may be considered 39 in reproductive terms).
Hormones such as AMH, FSH, and inhibin do not fully reflect egg reserve. The best method is counting antral follicles, which can be done at any time during the menstrual cycle.
Women aged 40+ with only 1–2 eggs have a very low chance of pregnancy with this method.
This is because more than 50% of embryos may be genetically abnormal. In addition, half of embryos may not match the desired gender, some may not reach maturity, and others may fertilize poorly.
Therefore, to achieve success, 8–10 or more eggs are typically required. The technique may cause partial damage to eggs. Women with very few eggs may have higher chances using CVS or donor eggs. For older women, egg donation is an alternative.
For successful egg donation, at least 15 eggs should be used, and the donor’s age is important—the younger the donor, the higher the chance of pregnancy.
2) Tubes and endometrium
As with standard IVF, fallopian tubes and the endometrium must be carefully evaluated.
3) Prior pregnancy and risk during egg collection
Women who have previously given birth may develop varicose veins around the uterus and ovaries, which can increase the risk of egg retrieval.
4) Experience of the center
Gender selection is among the assisted reproduction techniques requiring the highest level of expertise and experience. Choosing the right clinic is essential for a healthy pregnancy and a healthy baby.
How Does Gender Determination Work?
A baby’s gender is determined by chromosomes carried by the sperm. A sperm can carry either an X or a Y chromosome.
The woman’s egg contributes only an X chromosome. If the sperm carries a Y chromosome, the embryo will be male (XY). If the sperm carries an X chromosome, the embryo will be female (XX).
Gender Determination Combined with IVF
PGS/NGS testing is performed together with IVF in a controlled laboratory environment. A few days after fertilization, 3–6 cells are removed from each embryo at the blastocyst stage.
The cells are removed by a highly skilled embryologist using a laser and microscopic glass needle.
The biopsy taken from the trophectoderm does not harm the inner cell mass (ICM), which forms the baby.
Genetic structure and gender are analyzed by an advanced genetics laboratory.
Each embryo is assessed for quality and gender.
Only high-quality embryos of the desired gender are transferred.
Advantages of PGT / Gender Selection
Enables couples undergoing IVF to determine the baby’s gender in advance.
Helps select healthy embryos for patients with recurrent pregnancy loss.
May reduce risks linked to genetic issues in one or both parents through genetic screening.
Helps identify genetically abnormal embryos in women of advanced age.
Gender Selection and Future Family Balancing
If multiple embryos of different genders are identified, it is possible to request which gender will be transferred in the fresh IVF cycle.
To avoid multiple pregnancy, only one or two embryos of the desired gender are transferred. Extra embryos can be frozen for future Frozen Embryo Transfer (FET) cycles.
Legal Notice
The information on this page is provided for general informational purposes only, taking into account that non-medically necessary gender selection is prohibited under TRNC legislation.
This content is not medical advice, referral, or legal guidance, and does not encourage performing such a procedure in TRNC. Before making any decision regarding your personal situation, you must consult a specialist physician and, if needed, a legal advisor. Responsibility for the use of this content belongs to the user.