Sex Selection for Therapeutical and Non-therapeutical Purposes

By (embryologist), (gynecologist) and (babygest staff).
Last Update: 10/08/2019

Preferring a boy or girl when seeking pregnancy is common in society. New assisted reproduction technologies nowadays allow this possibility with guarantees and therefore, more and more couples are asking for the option of choosing the sex of their future baby.

Not all countries are in favor of sex selection simply because of parental desire and not for therapeutic purposes. Therefore, those whose legislation allows it receive numerous tourists motivated by the desire to have a child of the preferred sex.

Genetic analysis for therapeutic purposes

There are countries who consider the selection of sex or genetic manipulation for non-therapeutic or non-authorised therapeutic purposes to be a serious offence.

In some countries, the application of embryo selection techniques is only allowed in order to avoid the birth of children with serious genetic anomalies. Sex-linked diseases such as hemophilia or color blindness are generally suffered by men and therefore female embryos will be selected in order to prevent the development of the disease.

Spain, Russia, Canada or the United Kingdom rule out non-therapeutic selection, admitting gender selection with certain requirements for medical purposes.

On the contrary, countries such as the United States, Mexico, Jordan, Nigeria, Panama, Thailand and India allow the selection of sex for non-therapeutic purposes, i.e. for the sole purpose of fulfilling the wishes of the parents.

Sex selection in the United States

The United States is one of the most common countries in surrogacy because it has the most experience and legal guarantee. For both conventional in vitro fertilization (IVF) and surrogacy, sex selection of the embryos is permitted.

American legislation understands that it is possible for a couple to want family balance in order to experience the upbringing of both sexes.

Based on data from a U.S. sex selection study:

  • 26.6% want to have both boy and girl and 73.3% already had two or more children
  • Of the couples who choose sex, 48.4 per cent prefer girls and 51.6 per cent boys.

It is important to note that there is a balance of preferences between Western couples, which is not the case for couples from China or India who show a preference for the male gender.

About 50% of PGD treatments (a technique that allows genetic analysis of the embryo) carried out in the United States only seek to know the sex of the baby and not to determine the presence of any genetic anomaly.

How is the gender of the embryos selected?

There are two main techniques that make it possible to know the sex of the future baby before the transfer and subsequent implantation of the embryo, and even one of them before fertilization itself.

Preimplantation genetic diagnosis

PGD consists of extracting a cell from the embryo before the transfer and analysing its chromosomes so that we can know the sex of the embryo. This is the technique used in cases of therapeutic selection. Diagnostic reliability is close to 100%.

Semen Classification

Sperm sorting (MicroSort) is a technique that separates sperm according to weight and size. The spermatozoa with genetic endowment X have 2% more DNA and are larger in comparison with the spermatozoa with chromosome Y.

Once the spermatozoa have been separated, we will only use for in vitro fertilization those that have the chromosome of the sex we want, X if we want a girl and Y if we want a boy.

The reliability of this technique is not 100%. In fact, according to a U.S. study, the success rate when you want the female sex is 90% and when you want the boy it’s 73%.

FAQs from users

How is IVF performed with sex selection?

By Dr. Joel G. Brasch (gynecologist).

PGD is performed by biopsy of a blastocyst, sending some cells to the genetic laboratory and transferring the euploid embryo, i.e. an embryo with 46 chromosomes.

The patient will know the sex of the embryo and will be able to choose to transfer the embryo of the sex of her choice. PGD allows for more effective treatment and elective transfer of a single embryo.

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References

Authors and contributors

 Andrea Rodrigo
Andrea Rodrigo
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information about Andrea Rodrigo
Dr. Joel G. Brasch
Dr. Joel G. Brasch
Gynecologist
Dr. Joel Brasch is the Medical Director of Chicago IVF, founded in 2005. He is board certified by the American Board of Obstetrics and Gynecology, and has over 25 years of direct experience in fertility treatment and reproductive care. He is also the Director of Mount Sinai Medical Center’s Division of Reproductive Endocrinology and Infertility. More information about Dr. Joel G. Brasch
Adapted into english by:
 Romina Packan
Romina Packan
Babygest Staff
Editor and translator for the Babygest magazine in English and German. More information about Romina Packan

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