A group of US researchers propose a method with up to 80% success to select the sex of the embryo before fertilization
Choose the sex of the baby It has always been a desire when it comes to having offspring. But, at the time, it has unleashed ethical issues on whether this decision was based on a personal desire or if there was a medical issue behind it. A new work presented by a group of researchers from the USA has proven a new technique to select spermatozoa and thereby increase the chances that the embryo is of either sex. have managed to achieve a proven efficacy of around 80%.
The work, which has seen the light in the magazine Plos One, is made by Gianpiero D. Palermo, one of the pioneers credited with discovering ICSI or sperm microinjection. The authors of the article claim that sperm selection is more ethically acceptable than the selection of embryos using preimplantation genetic diagnosis (PGT-A), which does not affect the genetic load of the embryo. “We propose a new sperm sex selection technique (SST) that is shown to be safe and effective,” they explain in the publication.
“Although ethically debatable, expressing a sexual preference for offspring is popular among couples and is not limited to those undergoing infertility treatment. Sexual sperm enrichment, within a PGT-A protocol, allows for the selection of embryos for the desired sex. Our method of sex selection does not increase the proportion of additional aneuploid embryos [con anomalas cromosmicas]. Therefore, it can be considered extremely safe, as well as efficient, economical and ethically acceptable”, conclude Stephanie Cheung, Rony Elias, Philip Xie, Zev Rosenwaks, authors of the work together with Palermo, who carry out their activity at the Ronald Center for Reproductive Medicine. O. Perelman and Claudia Cohen in New York.
As explained by Roco Nez Calonge, embryologist, scientific director of the UR International Group and professor in the Reproduction Master’s Degree at the Complutense University and the Spanish Fertility Society, in statements to SMC, “The novelty lies in carrying out two groups using PGT-A to study chromosomal abnormalities in the resulting embryos., and in one of the two groups use the sperm selection technique that they propose. In this way, they compare between the two groups if the sperm selection technique for a certain sex is useful and safe and no more chromosomal abnormalities are found after its use”.
Although some countries such as the US allow This type of procedure is prohibited in Spain except in cases of prevention of diseases linked to sexual chromosomes.. Nez Calonge points out that “the authors of the paper propose that this technique could be used both for couples who want to select the sex of the baby out of personal desire and for medical reasons when there is a sex-linked disease, and that this would be more ethical than using PGT” .
For this reason, he adds that “from a purely medical point of view, The use of this technique when there are sex-linked diseases (such as hemophilia), would not be appropriate., since an 80% probability leaves the couple a 20% chance that the baby will not be of the chosen sex, giving rise to a person with the disease. However, if the selection is solely for personal reasons, this margin of error would be acceptable.”
It should be noted that the Palermo team mentions that there is a pitfall that limits this technique. “The sex of the embryo chosen for transfer is not known.. It may happen that, among several embryos obtained, although the majority are of the sex that has been wanted to obtain, the wrong one is chosen. From an ethical point of view, what happens to the rest of the embryos that are not chosen? What would be the fate of these?” says the embryologist.
In our country the selection of sex is not allowed unless there are medical reasons that justify it. “When the law was drafted in 1988, this question was raised based on the possible selection that certain groups could make to the detriment of the other sex and that would lead to an imbalance in the population,” recalls Nez Calonge. “Currently this prohibition does not make much sense, since the selection would be carried out by a small group of patients for personal reasons, and it would not imply an imbalance.”
Finally, the embryologist highlights that the use of the technique proposed by the Palermo team “It can be very useful in assisted reproduction centers since it is very simple (practically the same as what is usually done for semen preparation in laboratories)., and can make it easier for couples who wish to do so to increase the probability of obtaining a child of the desired sex. Of course, it is only an increase in that probability. It would be necessary to inform them well in advance and not offer certainties.
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