High-Precision Sex selection

Sex selection is useful not only for avoiding sex-linked hereditary diseases, but also for “family balancing”. Family balancing is the reduction of gender bias within a family. For example, sex selection is performed when the family has already had one or more children of one sex, and wishes to balance with a child of the opposite sex.

Humans usually have 44 autosomal chromosomes (1 pair each of chromosomes 1 to 22) and 2 sex chromosomes (X and Y chromosomes.) If the sex chromosomes are 2 X chromosomes, then the resulting baby will be female, or XX. If there is one X chromosome and one Y chromosome, it is a male, or XY. Since an always egg has one X chromosome and a sperm has either an X chromosome OR a Y chromosome, the sex of the child born is determined by the sex chromosome of the sperm.

X sperm are resistant to acidity, and Y sperm are resistant to an environment where the pH is inclined to alkali. Conventional sex selection uses this property along with the timing method several days before the ovulation day (the vagina is acidic) for girls, and the timing method on the day of ovulation (nearly alkaline in the vagina) for boys. Infertility clinics also handle sex selection jelly that controls vaginal pH.

In addition, X sperm has the property of being heavier than Y sperm, and when semen is layered in a special liquid and centrifuged, X sperm sinks to the bottom and Y sperm collects on top, so it is possible to do artificial insemination with a sperm sample that has more sperm of the desired gender. (Percoll method).

With either method, it is impossible to ensure sex selection, with a 60% to 70% chance of having the desired gender (50% chance of having the desired gender even without sex selection).

The only method of sex selection that can produce more certain results is the method using PGT-A.
PGT-A is a test that examines the number of chromosomes using cells of blastocysts (fertilized eggs 5 to 7 days after insemination). The DNA is extracted, amplified, and analyzed. By checking the sex chromosome pattern with PGT-A and selecting the embryo to be transplanted, you can select the desired sex with a success rate of almost 100%.

[Graph 1]　 Selection by PGT-A Report Sample

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