Many parents choose to chose the gender of their next child for various motives and values. Surprisingly, technological advancement now helps us to choose the gender of our future children with near-perfect precision. But what precisely does it take to decide on your child’s next gender, and how much does it cost to decide on a baby’s exact gender?

Fast facts about sex selection

While there are two major methods of gender selection, only one is universally known and used in the reproductive medicine community today. Other alternative hypotheses about diet and other trends exist, but they lack objective evidence and should not be taken seriously unless confirmed.

Since males and females have separate sets of sex chromosomes, sex selection is possible. Males have an XY chromosome pair, while females have a XX chromosome pair. The choice to pick sperm with the preferred X or Y chromosome or embryos with either XX or XY chromosome pairs allows parents to chose the gender of their fetus.

Gender allocation is not a service in and of itself.The preferred method for in vitro selection of a newborn baby (IVF) in conjunction with preimplantation genetic testing includes embryo testing – also known as PGS A.


How does gender selection work?

Two month old, boy and girl fraternal twin babies. They are sleeping and swaddled together in pink and blue wraps that are tied together in a bow.

A child’s sex or gender is determined by two chromosomes known as sex chromosomes. Female egg cells often bear the X chromosome, while male sperm may carry either the X or Y chromosome. If the X chromosome-containing sperm enters the mother’s egg, the embryo and eventual infant will be a female with the XX chromosome. If a Y chromosome embryo fertilized a woman’s egg cell, the resulting child would be a boy with an XY chromosome.

As you might be aware, there is a roughly 50/50 divide between boys and girls who conceive spontaneously. As a result, in order to confidently decide the gender of your prospective infant, you must be able to choose sperm with a Y chromosome or a fetus with an XY chromosome.

Form of sperm counting – sex sorting with IVF: imprecise and not commonly used

Sperm counting is a sperm sorting process that is based on the assumption that the X chromosomes have significantly more DNA than the Y chromosomes. Such techniques use a centrifuge to filter sperm, while others use a fluorescent dye to label the DNA. In theory, sperms containing X chromosomes will secrete according to density and end up downward on centrifugation and will shine brighter when using the fluorescent dye method.


Sex selection with IVF and fetal genetic testing

Sex identification using IVF and pre-implantation genetic testing is the most sophisticated way of selecting sex, with almost 100% precision. Several days after fertilization, a limited amount of cells extracted from IVF embryos are separated from the embryo and sent to a genetics laboratory for chromosomal analysis. The embryos are subsequently frozen after the biopsy to await the outcome of the genetic examination. Following the release of the findings, the planned parents decide whether to thaw the embryo and initiate the frozen embryo transfer. This procedure has an accuracy of more than 99.9 percent in determining the gender of the infant.


Detailed steps for IVF gender selection

Since careful sex selection necessitates in vitro fertilization, which is a very intensive process in and of itself, it is critical to consider, at the very least on a simple level, what the entire process entails. In general, IVF consists of four major steps:


Ovarian stimulation: A woman takes hormone-based drugs in order to produce a large number of fully grown, high-quality eggs (as opposed to the ones that are usually made).

Egg harvesting is the process of removing eggs from the ovaries.

Embryo lab: egg fertilization, embryo development for 3-7 days

Embryo Transfer: The act of returning an embryo to the uterus is known as embryo transfer.

Because determining sex requires an additional fetal test (it takes a number of days to obtain results from it), it not only requires additional steps for embryo testing, but it requires “two treatment cycles”. One involves making and testing embryos and the other, a frozen embryo transfer cycle that involves preparing the uterus for transfer and the FET itself.


Stage 1: Embryo making and testing cycle

This part of the treatment is identical to embryo freezing, which involves doing an IVF process and then freezing the embryos. Of note, a biopsy is taken and sent to a laboratory for examination until it is frozen.

Ovarian stimulation: As previously said, women take hormone-based drugs in order to produce a large amount of high-quality mature eggs. These stimulants usually begin on days 2-4 of a woman’s natural menstrual cycle and run for 10 days. More eggs = more embryos = more embryos of the desired sex = increased chances of achieving a live birth from an embryo of the desired gender.

Egg extraction: Once again, egg retrieval is the surgical process that harvests eggs from the ovaries. It normally happens about 12 days after starting the stimulant medications, but it can differ based on the drugs’ reaction and subsequent follicle / oocyte growth, which is assessed during ultrasound and blood test screening appointments. That is a minimally invasive surgical technique. It does not necessitate any incisions or stitches, and it does not necessitate the use of general anesthesia (which requires intubation and significant recovery time). Instead, the woman is sedated as an ultrasound needle is directed across the vagina and through the ovaries’ follicles. Once removed from the ovaries, the test tubes containing the follicular fluid and mature eggs are taken immediately to an embryology lab.

Embryo laboratory: The steps that take place in an embryology laboratory during sex selection can be divided into 5 main steps:

Isolation: Once the eggs enter the laboratory, the embryologist searches the follicular fluid and isolates any eggs that are found. It will be immediately placed in a nutrient medium that mimics the environment of the fallopian tube.

Fertilization: approximately 4 hours from the time of extraction, the embryos will be fertilized using ICSI or conventional fertilization methods.

Embryo development: After fertilization, embryos grow in the laboratory for 5-7 days. While in a standard IVF cycle, it is possible to transfer embryos after only 3 days (when they are in the cleavage phase of development) genetic testing can only be performed on blastocyst embryos that usually develop on the fifth day (but can develop a little later)

Embryo biopsy: After the embryo enters the blastocyst stage, it is made up of two kinds of fetal tissue. One of these pairs of cells will develop into an embryo, and the other will develop into the placenta. The biopsy is done using an extremely advanced, concentrated laser to extract a specific number of cells (usually 3-6 cells) from the group of cells that will form the placenta (called the ectoderm). These cells are then labelled, packaged appropriately, and sent to a third-party genetics laboratory for study.

Embryo Freezing: After the embryo biopsy, embryologists can vitrify (or quickly freeze) the embryo and hold it in almost equivalent condition to when it was young. Embryo freezing provides for the time needed to obtain genetic test results while having little impact on the accuracy or chances of future transition success. In particular, there is some evidence that a frozen move increases the chances of success for a significant proportion of IVF patients.

Genetic testing: A third-party genetics laboratory does the actual genetic research, and uses a technology known as the preimplantation genetic test for Aneuploides (PGT-A), which analyzes the number and type of chromosomes in each cell. Following chromosomal analysis, the set of cells belonging to a certain embryo would be identified as XY or XX, along with other essential details on the number of chromosomes in each cell. The planned parents and fertility clinic will now plan for the transfer of frozen embryos using a thawed embryo of the desired sex using this knowledge.


The second stage: Transfer of frozen embryos using an embryo of the desired sex

The transition of frozen embryos is much easier than the first stage of an IVF cycle, with only two major steps:

Endometriosis Manifestation: When inserting an IVF embryo, it is important to ensure that the uterus is in the best possible condition for the embryo to be inserted into the endometrium lining. Although it is possible to have a regular FET cycle without taking any drugs, it is strongly advised by doctors that a woman take estrogen and progesterone for a period of time before and after the embryo transfer.

Frozen Embryo Transfer: One of the embryos marked as the correct gender would be removed from cold tanks containing liquid nitrogen and thawed for embryo transfer using genetically tested embryos for gender selection. Once the embryos have been thawed, they will be inserted into a medical grade transfer catheter, which will be transferred through the vagina and cervix before being ejected through the uterus. The intending parent is now pregnant (until proved otherwise) with an egg that will grow into a fetus and an infant of their choice’s sex.