The Complete Truth About Gender Selection: One Clear Explanation

Many families preparing for pregnancy or going through IVF often ask:

Since gender is determined by sperm, is it possible to choose it in advance?Aren’t American labs advanced enough to sort sperm by weight or “washing”?

Today, let’s clarify what is real medical science, what is myth or psychological comfort, and how gender selection is accurately and legally done in the United States.

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1. Why Is Gender Determined by Sperm?**

A simple biological fact:

• Male sperm come in two types:

  X (which produces a girl) and Y (which produces a boy)

• Female eggs only contain X

After fertilization:

• X + X → Girl

• X + Y → Boy

Because the difference lies in the sperm, many people naturally wonder:

Can we pick the sperm we want?

Let’s look at the real science.

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2. Why the U.S. Does Not Recommend Microsort for Gender Selection**

   
   

Microsort is a method that separates X and Y sperm using dye + laser scanning.

It sounds scientific, but American clinics rarely use it. Why?

1) Safety concerns

The process requires staining the sperm and exposing it to strong light, which may damage DNA.U.S. regulations are strict: risk > benefit.

2) Accuracy is too low

• For selecting girls: 85–90%

• For selecting boys: 70–75%

This is far below the accuracy of embryo genetic testing (>99.9%).

3) It has not been fully approved by the FDA

Most U.S. clinics will not take risks in a sensitive area like gender selection.

4) A far better method exists: PGT

If something can achieve 99.9%, why use 70%?

👉 This is why Microsort is no longer mainstream in the U.S.

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3. What About the Popular Saying “Sperm Washing Can Separate X/Y”?**

   
   

Some people have heard things like:

• “X sperm are heavier and sink during washing”

• “Y sperm are lighter and float”

• “It may slightly increase the chance of a desired gender”

These stories do exist in the IUI community, but they are more like:

👉 Psychological comfort, not medical science

Why it has no scientific basis

• X sperm do contain a bit more DNA, but the difference is far too small to separate

• Sperm washing is designed only to remove debris and dead sperm

• There is no clinical method to sort X/Y sperm by weight

• It has never been included in ASRM guidelines

Families sometimes like the idea because it feels like they are “doing something,” but:

👉 It cannot be considered a gender-selection method.

These methods cannot determine gender anywhere in the world

• Sperm washing / layering

• Differences in sperm shape

• Embryo size or appearance

• Timing intercourse around ovulation

• Diet acidity/alkalinity

• Folk methods (salt/sweet consumption, calendars, etc.)

All of these are myths, not science.

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4. So How Does Gender Selection Actually Work in the U.S.?**

   
   

Only one method is accurate: PGT-A

Globally, and especially in the U.S., the only reliable way to select gender is:

✔ PGT-A (Preimplantation Genetic Testing for Aneuploidy)

Accuracy ≥ 99.9%

How it works

1. IVF to retrieve eggs

2. Embryos are grown to blastocyst stage (Day 5/6/7)

3. A few cells are biopsied and genetically tested

4. The report shows XX (girl) or XY (boy)

5. You choose which embryo to transfer

This is why the U.S. does not rely on outdated sperm-sorting methods—PGT is safer, more accurate, and fully transparent.

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5. Why Is Gender Selection More Reliable in the United States?

   
   

1) World-leading PGT technology

Most U.S. labs use the latest NGS platforms with the lowest error rates.

2) High success rates

For women under 35:

• 55–60% success per transfer

• 70–80%+ cumulative success rate

3) Strict laboratory standards

Dual CLIA + CAP accreditation—rare globally.

4) Legal and transparent

U.S. law allows family balancing, even for single individuals.

5) Public, verifiable data

CDC and SART publish yearly statistics—extremely high transparency.