MOSCOW, April 1, Vladislav Strekopytov. Specialists have developed a simple and safe technique that ensures the birth of a child of a certain gender with an 80% probability. The method is based on the sorting of spermatozoa by weight, which is carried out at the stage of genetic testing before IVF.
It all depends on the man
There are many «folk recipes» on how to influence the sex of the unborn child: eat certain foods, choose a special day for conception, and so on. Basically, all this is myths or grandmother's tales, not supported by science.
The sex of the embryo is formed during the fusion of the egg and sperm. At the same time, a woman can only pass on the X chromosome to her unborn child, and a man can pass on both X and Y. In fact, the female body is not involved in determining the sex of the baby. Who will be born — a boy or a girl — depends only on the man.
Girls are born when an egg with an X chromosome is fertilized by a sperm with the same chromosome, boys — with a Y chromosome. Of all the many spermatozoa, one wins, and it is impossible to predict which will be more viable, «male» or «female». With natural conception, this process is random, it cannot be programmed. Another thing is if a person intervenes.
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«Scales» for sperm
There are different laboratory methods for sexual selection of sperm — using gel filtration , electrophoresis, atomic force microscopy, flow cytometry with fluorescent labeling, and others.
All of these methods have limitations. Some are very time-consuming, others require expensive equipment and materials, and others do not provide a guaranteed result. In addition, it is not known how safe they are. Any physical intervention can disrupt the DNA structure.
Researchers at Cornell University College of Medicine have come up with a simple and effective technique for separating «male» and «female» spermatozoa that they say could be applied in clinical practice tomorrow.
The method is based on weight differences. The authors found that spermatozoa with the X chromosome are heavier. Therefore, in a liquid medium with a density gradient, «female» cells are concentrated in the lower layer, and «male» cells in the upper one. type=»photo» data-crop-ratio=»0.458″ data-crop-width=»600″ data-crop-height=»275″ data-source-sid=»cc_by_40″ class=»lazyload» width=»1920 «height=»879″ decoding=»async» />
From August 2016 to July 2020, scientists conducted an experiment in which more than 1,300 American couples who underwent genetic testing before IVF took part. Of those who did not have any special preferences regarding the sex of the unborn child (and they turned out to be the majority — about 92 percent), a control group was formed, where the IVF procedure was standard. But 105 couples wanted to have a child of a certain gender, and they had a preliminary sperm separation.
As a result, in the control group, 45.3 percent of the embryos were female, and 54.7 — male. At the same time, among the 59 couples who were determined to have a girl, 79 percent of the embryos were female, and out of 46 couples who wanted to have a boy, almost 80 received it.
The authors note that the new method, although it does not guarantee a 100% result, increases its probability. With high efficiency, the new technology is relatively cheap and absolutely safe. All participants in the study had healthy children, and by the age of three, none of them had any serious health problems or developmental delays. jpg» media-type=»photo» data-crop-ratio=»0.833333333333333″ data-crop-width=»600″ data-crop-height=»500″ data-source-sid=»rian_infographics» class=»lazyload» lazy=»1″ />
IVF Opportunities
It is still possible to technically determine the sex of an embryo before implantation — with IVF with preimplantation genetic testing (PGT). However, in Russia and some other countries, «ordering» a boy or a girl will not work. Federal Law No. 323-FZ of November 21, 2011 «On the Fundamentals of Protecting the Health of Citizens» allows this procedure only for medical reasons.
We are talking about cases where there is a risk of developing hereditary diseases transmitted exclusively through the male or female line, such as hemophilia, color blindness, rheumatoid arthritis, Duchenne-Becker muscular dystrophy, Jacobs syndrome and others.
PGT is a complex and expensive screening study , which is not included in the standard IVF procedure. It is also called an embryonic biopsy — before freezing, a small number of cells are taken from the embryos created «in vitro» for testing.
The main objective of the method is to identify genetic defects associated with hereditary diseases and to determine the total number of chromosomes. The health of the unborn child also depends on this. For example, people with Down syndrome are known to have one extra chromosome.
According to statistics, chromosomal abnormalities are present in about half of the embryos created through IVF, and they account for about 70 percent of early miscarriages. The use of PGT primarily reduces the likelihood of an unsuccessful pregnancy. The definition of gender in this case occurs along the way.
In countries such as the USA, Cyprus, Mexico, Thailand, it is allowed to carry out selection by the PGT method «for the purpose of gender balance in the family.» That is, a couple can choose the sex of their unborn child in the absence of medical reasons only if they already have at least one child of the opposite sex. In the US, the cost of such a service is from ten to 20 thousand dollars. «0.671666666666667» data-crop-width=»600″ data-crop-height=»403″ data-source-sid=»rian_infographics» class=»lazyload» lazy=»1″ />
Ethics and law
Many scientists consider the sexual selection of embryos to be ethically unacceptable. In addition, there is no legal regulation.
«Sex selection of embryos without extenuating circumstances, such as a sex-related disease, is illegal,» Darren Griffin, professor of genetics at the University of Kent, explains in an interview with The Irish News. semen sharing could be a legal loophole.»
The difference between the new technology and the previous ones is that it uses standard tests on sperm and embryos approved by the medical services of most countries.
«I'm worried that this technology could become widely used in clinical practice,» says the head of the department of andrology at Imperial College London Dr. Channa Jayasena «The results strongly suggest that the method allows the selection of sperm that determine the sex of embryos. However, the serious ethical issues raised by the study are far more important than the technical advances. Manipulating the sex of the offspring could lead to detrimental consequences for society.» that in the future this method will be adapted for selection for other traits laid down at the gene level, such as, for example, eye or skin color. And here it is already close to eugenics.