Gender selection

Gender selection

What is gender selection?

It means that a couple who wishes to have a child of either gender takes measures to have a child of the desired gender through the use of some method. Human gender is determined by the combination of two sex chromosomes (X and Y chromosomes), XY for males and XX for females. The egg and sperm contain half of both parents’ chromosomes, but the egg (female-derived) contains only an X chromosome, while the sperm (male-derived) contains both X and Y chromosomes. The gender selection method uses this principle to sort sperm for IVF into sperm with an X chromosome and sperm with a Y chromosome in advance. Then, using sperm of the desired gender for both males and females during IVF, a fertilized egg of the specific gender is created and implanted in the uterus. The sperm sorting method used at our clinic is MicroSort®.

Our gender selection method

Although a certain number of patients desired gender selection in the past, the only scientifically based method of practicing gender selection was IVF using PGT-A (Preimplantation Chromosome Testing). However, using PGT-A solely for gender selection has many ethical problems, and its use in general clinical practice has been problematic. We have decided to introduce a new high-precision gender selection method using MicroSort® provided by ChromoS, Inc. MicroSort® is a test method that classifies the sex of sperm based on the amount of DNA contained in the sperm. Since X sperm (girls) contain about 2.8% more total DNA than Y sperm (boys), by detecting the difference in the amount of DNA in the sperm, the test identifies whether the sperm are X sperm (girls) or Y sperm (boys) and classifies them.

Inspection methods with MicroSort®

Upon arrival at the laboratory, the semen is washed to remove the liquid portion of the semen and low motility sperm, leaving only sperm with a high probability of pregnancy. The DNA is then stained using a special fluorescent material that bonds to the DNA in the sperm only for a certain period. The temporarily stained sperm are then analyzed in a flow cytometer device. The DNA material in the sperm emits light when illuminated by the laser, and X sperm (girls), which have more DNA, glow brighter than Y sperm (boys). By measuring the degree of fluorescence and luminescence using dedicated software, it is possible to identify and classify only the sperm of the desired sex at the time of application for testing.

For patients who wish to have gender selection

Patients who wish to undergo gender selection with MicroSort® must first sign an individual contract with ChromoS, Inc. Our clinic will inform you of the contracting procedure and the treatment flow after the contract has been signed. Please feel free to contact our clinic if you are considering the high-precision gender selection method using Microsort®.

Success rates for gender selection

The success rate of gender selection with MicroSort® is 93% for girls and 82% for boys, based on more than 1,500 follow-up studies conducted in the United States. This is the second highest success rate after preimplantation diagnosis, which is 99% accurate in determining the gender of a fertilized egg by preimplantation diagnosis. The final pregnancy rate with MicroSort® treatment is almost equal to that of a typical natural pregnancy. (As for the probability of natural pregnancy, it is generally considered to be over 50% for women aged 19-26, about 40% for those aged 27-34, and about 30% for those aged 35-39.)

Decrease in sperm count

In the process of performing MicroSort®, the number of sperm is always reduced due to the repeated freezing and thawing operations. The U.S. development institution for MicroSort® considers a recovery rate of 1.5% or more above the original sperm count to be the standard figure, and at present most patients are within this range. Thus, to accommodate the reduction in sperm count due to the process of using MicroSort®, it is necessary to assume ICSI in gender selection treatment. (As is the general IVF process, egg retrieval, ICSI, embryo freezing, and embryo transfer are all required.)


  • The price includes the cost of ovulation induction, hormone testing, ultrasound, egg retrieval, and embryo freezing.
  • The price will vary depending on the final number of eggs retrieved and the number of embryos frozen.
  • The price is only an estimate and may vary depending on the patient’s situation.
①MicroSort® usage fee¥498,000
②In vitro fertilization using sorted sperm¥500,000〜¥1,000,000
Total Amount①+②
In Japanese yen as of 2023. Subject to change without notice.


Since the opening of our clinic, we have listened to the wishes of many couples who wish to have children and have worked diligently to fulfill as many of those wishes as possible. Considering the recent social trends for diversity, we would like to present treatment options that meet the needs of our patients who wish to have a child or children of the desired gender. We will do our best to fulfill as many dreams of couples as possible.

Reservations & Inquiries

How to make an appointment

  • Consultations are by appointment only.
  • Please make your first appointment by phone or web appointment.

If you have any questions about our treatment methods, policies, or anything else, please feel free to contact us.