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Global Methods of Sex Selection

Global Methods of Sex Selection | วิธีการเลือกเพศลูกมีกี่ประเภท? ทำความรู้จักวิธีการเลือกเพศลูกที่ได้รับความนิยมทั่วโลก

Global Methods of Sex Selection

Sex selection is used globally for a number of reasons. It may be for medical reasons, such as to avoid and prevent severe sex-linked diseases inherited in your family, or for non-medical reasons, such as to balance your family, to have another baby of the same sex as a deceased child, cultural values, etc. There are a variety of sex-selection methods, but which ones are effective, which are safe, which are reliable, etc.?

               In this article, Superior A.R.T., a leading fertility clinic, summarizes some information on some global methods for sex selection. These can be grouped into three types, Natural Methods, Sperm Sorting Methods, and Preimplantation Genetic testing Methods (PGT).

               Today, we’ve got the answers for you. Let’s find out.

  1. Natural Sex Selection Methods
  2. Sperm Sorting Methods
  3. The PGT (Preimplantation Genetic Testing) Method with IVF/ICSI

1. Natural Sex Selection Methods

Natural methods that rely on changes in the physical or physiological conditions, and include Shettles technique, Whelan Method, Billings Ovulation Method, pre-conception diet, and gender selection kits such as GenSelect and Smart Stork. They rely on timing of intercourse, the vaginal environment, changing diet, and ingestion of supplements.

  • Timing methods aim to affect the sex ratio of the resultant children by having sexual intercourse at specific times as related to ovulation. They also often require the woman keep ovulation tracking records.  They may also suggest certain sexual positions as having an effect on the selection of sex. Studies have not been consistent about whether timing methods have any influence on the sex of the baby, with some showing no correlation and others showing just the opposite. These methods include the Shettles Method, the Whelan Method, and the Babydust Method.
  • Dietary methods require, as its name suggests, that the mother, and perhaps the father as well, eats a certain diet for a period of time prior to before conception, and that it will play a very influential role in whether she will conceive a girl or a boy. These methods often combine the timing of intercourse with dietary changes. While several studies have concluded that the combination of maternal diet with timing of intercourse is capable of increasing the probability of conceiving a girl, other studies have been less conclusive. There is also no systematic guide to which foods and supplements to take.
  • Special Supplements methods, such as GenSelect, use specially-formulated “nutriceuticals” in combination with dietary guidelines for mothers and fathers, intercourse timing aids, and vaginal environment adjustment instructions. These are proprietary products.

2. Sperm Sorting Methods

These include sperm sorting by gradient (eg. Ericsson’s method), various other sperm sorting techniques, and MicroSort.

  • Sperm sorting by gradient

These methods rely on passing the sperm through a column containing a gradient of either various additives, or of varying concentrations. They rely on the small difference in mass between the X and the Y bearing sperm to influence how far the sperm will penetrate the next layer. The different layers become concentrated with sperm of one particular sex.

The Ericsson method uses higher concentrations of sperm of the desired sex to increase the likelihood of conceiving that sex. When used to increase the likelihood of a female child, studies have resulted in between 70% and 80% female children. When used to increase the likelihood of a male child, studies have resulted in between 50% to 75% male children

  • Other sperm sorting techniques

There are several other sperm sorting techniques, such as swim-up which relies on supposed difference in the speed at which X and the Y bearing sperm swim to concentrate the sperm. These methods lack any scientific support.

  • MicroSort

MicroSort is an advanced technique that sorts sperm “in vitro” by flow cytometry. Semen is labeled with a fluorescent dye. As the X chromosome is larger (i.e. has more DNA) it will absorb a greater amount of dye than its male (Y-chromosome bearing) counterpart. During flow cytometry, X spermatozoa fluoresce brighter than Y- spermatozoa, and this is used to separate them. It does not completely separate them and each sample is tested and a percentage concentration given. The technology was trialed on humans in the US and claimed up to a 90% success rate. However, it was banned for human use by the USFDA and the laboratories moved to other countries.

Although the natural sex selection methods are free and can bring a miracle to many couples and families from time to time, it is still undeniable that its success and certainty is almost impossible to predict.

3. The PGT (Preimplantation Genetic Testing) Method with IVF/ICSI

If now you are asking then what is the most effective, reliable, and safest sex-selection technique, then the answer is PGT or Preimplantation Genetic Testing together with IVF.

Preimplantation Genetic Testing is a technique used to identify known family genetic disorders and/or general chromosomal defects in embryos created through an In Vitro Fertilization (IVF) cycle. Eggs are fertilized with the partner’s sperm and grown in culture until day 5 or day 6 “blastocyst” stage. A few cells are biopsied from each embryo and can be tested using advanced genetic techniques such as Next Generation Sequencing (NGS).

This method accurately detects the embryos chromosomal complement including the sex chromosomes and therefore the embryo’s sex.

The method is not only very reliable and accurate, it also allows only the transfer of an embryo with a normal chromosomal number, the healthiest embryo, and therefore healthier pregnancies and less risk of defects in the fetus or the newborn baby.

However, because the PGT Method with IVF is the most expensive approach of all, many couples often opt for one of the other cheaper options instead. You should still always consult with a specific IVF clinic of your choice, as many may offer a discount, a promotion, or a special package that could be very affordable to you.


While the natural sex selection methods are by far the simplest and cheapest (many free of charge), and may be most suitable for couples who are just simply enjoying the idea of maybe getting a boy over a girl or a girl over a boy, their unpredictability and uncertainty makes them unsuitable if you are seriously only wanting to conceive a child of a specific sex (eg. to prevent passing on your sex-linked genetic disease). In that case, only the assisted techniques are recommended, and the only truly accurate way is with using the PGT with IVF Method.

Additionally, if you have tried every natural way to get pregnant or to conceive a child for more than 1 year already, it is also a sign to start thinking about more advanced assisted approaches such as IVF/ICSI.  In Vitro Fertilization (IVF) is by far one of the world’s most proven and effective infertility treatments. For more information on what IVF is or what steps it includes, you can read it here.

About Superior A.R.T.

Superior A.R.T. was founded in 2007 by a group of leading Thai Infertility specialists in collaboration with Australian world leading fertility and A.R.T. treatment providers. Superior A.R.T is a renowned fertility clinic offering comprehensive fertility, IVF, IUI, ICSI, Egg Freezing, PGT, and genetic services by a team of experienced treatment providers and researchers specifically specializing in Assisted Reproduction Technology – A.R.T. Superior A.R.T. is committed to making your dream of having a healthy baby come true.


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