MicroSort Gender Selection: How sperm sorting with MicroSort® and IUI really works – and why it may not be your best option
When is MicroSort the right option for sex selection?
Not every woman who dreams of a baby of the desired gender feels comfortable going through IVF. For some, embryo testing – especially when it involves preimplantation genetic diagnosis – feels like too much. That’s where MicroSort® comes in. It’s often marketed as the least invasive gender selection method, especially for those who want to avoid embryo transfer or fertilisation in the lab. Instead of using IVF to test embryos, MicroSort® works by sorting sperm before insemination.
This method is often chosen for personal or ethical reasons. Women who wouldn’t feel okay discarding embryos, or who want a more “natural” approach, see sperm sorting as a gentler way to influence the outcome. The MicroSort® procedure is typically combined with IUI – a process where the enriched sperm sample is placed directly into the uterus around ovulation. It sounds simple, and the idea of using sperm sorting to avoid complex assisted reproductive techniques is tempting. But whether this is the right option depends on how strongly you want a certain result – and how comfortable you are with the level of uncertainty.
Ethical reasons for choosing sperm sorting instead of embryo testing
There are many reasons why some women prefer not to use preimplantation genetic testing. For example, the idea of choosing one embryo over another can feel like crossing a line. Even though IVF has helped millions of families, the process can seem too clinical – and too far from what they imagined when they first thought about having a baby. Some also have religious or cultural concerns about fertilisation outside the body or the use of genetic selection.
MicroSort® offers a different path. It doesn’t require embryo creation or selection. Instead, it separates sperm cells into two groups: those carrying the X chromosome and those carrying the Y chromosome. The sperm sample is washed, stained with a fluorescent dye, and then analysed by a flow cytometer – a machine that can distinguish between the two types of sperm by detecting the difference in the amount of genetic material. This is known as sperm separation technology. The result is an enriched sperm sample ready for insemination – one that is more likely to produce the desired gender, although the result is never guaranteed.
Understanding the emotional and medical reasons behind MicroSort®
For many couples, MicroSort® is not about avoiding IVF – it’s about hope. Some have multiple children of the same sex and are now hoping for balance. Others may have lost a child or want to avoid passing on a sex-linked genetic condition. Whatever the motivation, the emotional side of choosing the baby’s sex is always present.
That’s why MicroSort® is often chosen as a preconception method. It allows couples to try for a baby without selecting embryos, yet still with a higher percentage of sperm cells for the desired gender. But this method based on the difference between X- and Y-bearing sperm comes with limitations. The number of sperm cells that can be sorted depends on many factors – and the low number of sperm after the sorting process can reduce the overall chances of success. Some women invest emotionally and financially in MicroSort®, only to face disappointment if pregnancy doesn’t occur – or if the baby turns out to be the opposite sex.
Why MicroSort® may not be the next step on your fertility journey
If you’ve been looking into gender selection and came across MicroSort, you might be wondering if this is the easiest way forward. It’s less invasive than IVF, it avoids embryo selection, and it sounds like a more natural process. But for many women, especially those hoping for reliable results, MicroSort can be misleading.
The method is based on the idea that sperm carrying the X chromosome has more genetic material than sperm carrying the Y chromosome. A flow cytometer is used to sort the semen sample by detecting the difference in that amount. While the idea sounds scientific, the reality is more uncertain. MicroSort is not FDA-approved, and many clinics no longer offer it. It’s not widely available in Europe either — although some still travel to MicroSort® lab locations or countries like Cyprus, where access to this technology may still exist.
The bigger issue is the unpredictability. Even with a carefully prepared sperm sample, fertilisation still depends on timing, motility, and biological chance. The enriched sperm sample ready for use may contain fewer healthy cells after the staining process, and the overall success rates — both for getting pregnant and for having the baby of the desired gender — are lower than with IVF. If your personal situation already involves fertility challenges, the MicroSort procedure may simply not give you the clarity and reassurance you need.
How MicroSort® technology based sorting works
The basic idea behind MicroSort sounds simple: separate sperm cells based on whether they are likely to produce a boy or a girl. But the actual procedure is highly technical, and the outcome less predictable than many assume. MicroSort® is based on a sorting technology that claims to increase the chances of having a baby of the desired gender — but it does not guarantee the result. Understanding how the method works helps put its promises into perspective.
The MicroSort procedure begins with a semen sample that is prepared in a laboratory. The sperm is stained with a fluorescent dye that binds to DNA. Because sperm carrying the X chromosome has slightly more genetic material than those carrying the Y chromosome, the flow cytometer can detect the difference. It then separates sperm into two groups: X-bearing (for a girl) and Y-bearing (for a boy). The enriched sperm sample is then used for insemination — most often IUI.
This method for separating sperm cells is technically impressive but comes with trade-offs. The staining and sorting process can reduce the number of viable sperm cells available. The end result is often a low number of sperm, which can affect the chances of fertilisation. It’s not a quick fix — and the science behind it, while fascinating, is not as exact as many couples might hope.
The method for separating sperm cells by sex
MicroSort uses a flow cytometer to sort sperm based on the small difference in DNA content between X- and Y-bearing sperm. The sperm sample is stained with a fluorescent dye, allowing the machine to measure how much DNA is inside each cell. This method is what makes the MicroSort® technology based approach possible — it literally separates sperm by how much light they emit when excited by lasers.
The X-bearing sperm, which contain more genetic material, shine brighter under the flow cytometer. The Y-bearing sperm shine slightly less. Based on this, the machine sorts the cells into two groups. The goal is to create an enriched sperm sample that increases the odds of fertilisation with the desired sex. But this process is not without consequences: staining, sorting and mechanical pressure can reduce sperm motility and quality, which may affect the final outcome.
Why sorted sperm is mostly used for IUI – not IVF
Even though MicroSort is related to IVF in the broader context of assisted reproductive techniques, it’s rarely used in combination with in vitro fertilization. The main reason is that MicroSort was originally intended to be used for IUI — a less invasive option where the selected sperm is placed directly into the uterus.
There are several reasons why MicroSort is not widely combined with IVF. First, because IVF already allows preimplantation genetic diagnosis, the need to sort sperm before fertilisation is less relevant. Second, the number of sperm cells after sorting is often too low for advanced techniques like ICSI, where a single sperm injection is used. Finally, IVF clinics tend to prefer more reliable methods when sex selection is involved. Most patients who use MicroSort are not facing infertility, but are looking for a non-invasive way to increase the chances of having a boy or a girl. This is why the IUI option remains the most common path for couples using MicroSort.
How MicroSort® technology based sorting works
The basic idea behind MicroSort sounds simple: separate sperm cells based on whether they are likely to produce a boy or a girl. But the actual procedure is highly technical, and the outcome less predictable than many assume. MicroSort® is based on a sorting technology that claims to increase the chances of having a baby of the desired gender — but it does not guarantee the result. Understanding how the method works helps put its promises into perspective.
The MicroSort procedure begins with a semen sample that is prepared in a laboratory. The sperm is stained with a fluorescent dye that binds to DNA. Because sperm carrying the X chromosome has slightly more genetic material than those carrying the Y chromosome, the flow cytometer can detect the difference. It then separates sperm into two groups: X-bearing (for a girl) and Y-bearing (for a boy). The enriched sperm sample is then used for insemination — most often IUI.
This method for separating sperm cells is technically impressive but comes with trade-offs. The staining and sorting process can reduce the number of viable sperm cells available. The end result is often a low number of sperm, which can affect the chances of fertilisation. It’s not a quick fix — and the science behind it, while fascinating, is not as exact as many couples might hope.
The method for separating sperm cells by sex
MicroSort uses a flow cytometer to sort sperm based on the small difference in DNA content between X- and Y-bearing sperm. The sperm sample is stained with a fluorescent dye, allowing the machine to measure how much DNA is inside each cell. This method is what makes the MicroSort® technology based approach possible — it literally separates sperm by how much light they emit when excited by lasers.
The X-bearing sperm, which contain more genetic material, shine brighter under the flow cytometer. The Y-bearing sperm shine slightly less. Based on this, the machine sorts the cells into two groups. The goal is to create an enriched sperm sample that increases the odds of fertilisation with the desired sex. But this process is not without consequences: staining, sorting and mechanical pressure can reduce sperm motility and quality, which may affect the final outcome.
Why sorted sperm is mostly used for IUI – not IVF
Even though MicroSort is related to IVF in the broader context of assisted reproductive techniques, it’s rarely used in combination with in vitro fertilization. The main reason is that MicroSort was originally intended to be used for IUI — a less invasive option where the selected sperm is placed directly into the uterus.
There are several reasons why MicroSort is not widely combined with IVF. First, because IVF already allows preimplantation genetic diagnosis, the need to sort sperm before fertilisation is less relevant. Second, the number of sperm cells after sorting is often too low for advanced techniques like ICSI, where a single sperm injection is used. Finally, IVF clinics tend to prefer more reliable methods when sex selection is involved. Most patients who use MicroSort are not facing infertility, but are looking for a non-invasive way to increase the chances of having a boy or a girl. This is why the IUI option remains the most common path for couples using MicroSort.
“When it comes to choosing your baby’s sex, clarity matters more than promises. MicroSort® may sound gentle — but only IVF with PGT-A can truly give you answers.”
Nathalie Wiederkehr
Does MicroSort® increase your chances of having a boy or a girl?
When you’re looking into gender selection, MicroSort® seems like a promising option — at least on the surface. The idea that you can sort sperm and simply choose the sex of your baby feels almost too good to be true. And in some ways, it is. While MicroSort® can shift the odds slightly in favour of one sex, the method does not guarantee the outcome — and the success rates depend on many factors, including the quality of the sperm, the woman’s age, and the timing of ovulation.
The technique is often promoted with statistics, but not all clinics report the full picture. And since MicroSort is not FDA-approved and no longer part of official trials, there is limited independent data. It’s important to understand what the numbers actually mean — especially if you’re hoping for a clear result and not just a slightly higher chance.
What the statistics really show about fertilisation and success rates
According to older published data, MicroSort was said to increase the chances of having a girl to around 91 percent, and a boy to about 76 percent. But these numbers came from early research, often from the Genetics and IVF Institute that developed the method. Since then, independent studies have been rare, and most newer IVF institutes no longer provide MicroSort.
In practice, the numbers vary. Fertilisation with sorted sperm doesn’t guarantee that the embryo will carry the expected chromosome. The process itself — from semen analysis to staining and flow cytometry — affects the number of sperm cells and their motility. Even after sorting, the percentage of sperm cells carrying the desired chromosome can vary. With IUI, timing must be perfect, and even then, fertilisation is not guaranteed. With no embryo testing, you won’t know the result until much later in the pregnancy. For women hoping to avoid disappointment, this can be a serious drawback.
Risks you should know before choosing sorting technology
The MicroSort procedure may seem gentle, but it comes with its own risks. First, staining the semen with fluorescent dye can affect the sperm’s ability to fertilise an egg. The flow cytometer subjects each sperm cell to pressure, heat and laser exposure, which may reduce quality. The number of sperm cells available for insemination is often much lower after sorting — and if the initial sperm sample has limited motility, that problem only increases.
Another concern is emotional. When a method is presented as a scientifically proven preconception technique, people tend to expect clear results. But MicroSort® is not a guarantee — and that’s where the disappointment often starts. Couples invest time, money and hope, only to learn months later that the baby’s sex wasn’t what they expected. For some, that emotional cost is heavier than they imagined. Especially in a context like gender selection, clarity matters — and MicroSort may not be the most transparent path.
Where to get access to this technology today
MicroSort® is no longer widely available. After clinical trials in the United States were stopped and FDA approval was not granted, most clinics removed the service from their programs. Today, only a few locations continue to provide MicroSort — and even those may not offer it consistently. Some couples still choose to travel to MicroSort® lab locations abroad, often to countries like Cyprus, where the method is sometimes included in broader assisted reproductive programs. But access to this technology remains limited and sometimes poorly regulated.
Women searching for options are often surprised to learn how few IVF clinics still support this technique. Even though it’s still mentioned online, active programs are rare. And those that do offer it often do so quietly, without updated data or transparent success rates. It’s essential to ask specific questions if you’re considering this method: Where is the sperm sorted? Is a semen analysis done beforehand? What happens if the number of sperm cells is too low after the sorting process? These are important details — and unfortunately, many clinics don’t offer clear answers.
Why most clinics stopped offering MicroSort®
There are a few reasons why clinics around the world — including major IVF institutes — no longer provide MicroSort. The first is scientific: the results weren’t as reliable as hoped. The method is based on the difference in DNA content between X and Y sperm cells, but that difference is small, and the method based on the difference doesn’t always deliver usable results.
Second, the equipment and training needed — such as the flow cytometer and staining protocols — are expensive and technically demanding. In some cases, the low number of sperm after sorting made it impractical for standard use. Clinics focused on advanced fertility care and a wide variety of assisted reproductive techniques tend to prefer more predictable solutions. And finally, without FDA approval or consistent international standards, many simply stopped trusting the long-term potential of the MicroSort technology.
Safer alternatives if you’re planning gender selection
If you’re serious about sex selection and want more clarity than MicroSort can offer, there are more reliable options. IVF with preimplantation genetic testing is currently the only scientifically proven method that can confirm the embryo’s sex before implantation. While IVF may seem like a bigger step, it offers more transparency — and for many women, the emotional safety of knowing is worth it.
In places like North Cyprus IVF Centre and similar clinics abroad, a wide variety of assisted reproductive techniques are available — often at lower costs than in the US. These clinics don’t offer MicroSort IUI but provide other services that may help you achieve your goal. Options like IVF with PGT-A, sperm injection (ICSI), or egg donation are part of a modern approach to family planning. Choosing a baby of the desired gender is still a delicate subject — but if you want clarity, predictability, and the highest chance of success, these alternatives are worth exploring.
Your next steps
If you’re thinking seriously about gender selection and want to understand what’s really possible today — without falling for marketing promises — our free guide can help. It gives you an overview of IVF options in Europe, explains where gender selection is allowed, and includes an example from a clinic in North Cyprus with real-life costs and average success rates.
Still unsure what’s right for you? You can also book a private call with us. We don’t recommend sperm sorting – but we do believe that IVF with PGT-A is the only reliable way to plan for a baby of the desired gender.
Download the guide and get clear on your options — so you can move forward with confidence.
