Ultrasound – What to Know About & Learn Baby’s Gender

A patient enters the ultrasound room, despair in her eyes: “Doctor, my husband said, if there is a girl, not a boy, I will leave!”

I want to remind demanding dads that the man determines the sex of the child, or rather, his spermatozoa, which carry the X (girl) or Y (boy) chromosome. If women reproduced by parthenogenesis (asexually), they would only have girls.

Nevertheless, the desire of future parents to find out as soon as possible is understandable: what color of sliders to prefer in the available store abundance?

As an expert, I want to warn you: take your time! Firstly, it rarely happens that doctors recommend doing an ultrasound examination solely to determine the sex of the child. Medical indications for sex determination include the possibility of hereditary diseases associated with the X chromosome (for example, hemophilia – blood in coagulability disease), which affects only boys; the need to identify specific genetic conditions, the definition of twins. Secondly, according to world standards, ultrasound of the fetus is performed within a strictly defined time frame. The first one is 12-13 weeks. At this time, the presence of gross malformations (absence of limbs, brain, etc.) is revealed. The subsequent ultrasound examination is performed at 23-25 ​​weeks when the anatomy of the fetal organs is best visible. Finally,

The age difference between parents affects the sex of the child.

A couple of years ago, the English journal Nature published the results of a study conducted by British scientists who concluded that in a marriage where the husband is older than the wife, the birth of the firstborn boy is much more likely. In a family where the wife is older than the husband, the situation is reversed – the first is more likely to be born a girl. Curiously, this pattern applies only to firstborns.

Indeed, statistical studies have shown that in 57 families where the husband is older than his wife (by 5-17 years), the ratio between the firstborn boys and girls was, respectively, 37 to 20. While 43 couples in which the wife is older (the difference was from 1 year to 9 years) gave birth to 14 sons and 29 daughters (again, we are talking about the firstborn).

The researchers looked at the histories of many families in England and Wales from 1911 to 1952. and found the exact relationship between the difference in the age of the spouses and the sex of the firstborn.

So, according to British doctors, men who long for a son should choose a young wife for themselves, and women who dream of a daughter should look for a father for their child among younger men.

Attempts to explain this phenomenon from a biological point of view are still unsatisfactory. Perhaps this difference in age leads to a higher frequency of early miscarriages of embryos of the corresponding sex.

The accuracy of determining the sex of the fetus depends primarily on the duration of pregnancy and, unfortunately, on the experience of a specialist. Until the 8th week of development, the genitalia of the embryo is not differentiated. The process of their formation ends by 10-12 weeks of pregnancy. But do not torment the doctor with the standard question “Who will I have?” at the first ultrasound (at 12-13 weeks). According to most scientists, identification of the sex of the fetus is possible only from the 15th week of pregnancy.

The accuracy of determining the sex of the fetus

The definition of a boy is to find the scrotum and penis; girls – in the visualization of the labia majora.

One of the mistakes in identifying the sex of the fetus is the mistaking of the loop of the umbilical cord or fingers of the fetus for the penis. Sometimes girls in utero experience a passing swelling of the labia with time, which is mistaken for the scrotum. There are cases when the fetus “hides” manhood behind tightly compressed legs and, due to its excessive modesty, “calls” a girl.

The optimal time to answer the cherished question is 23-25 ​​weeks of pregnancy. The fetus is quite mobile and, with the patient persistence of the ultrasound doctor, will most likely show who he is. With a full-term pregnancy (from 37 weeks), determining the sex of the fetus is difficult due to its large size and low mobility.

I am often asked the question: is it possible to determine the sex of a child not visually, using ultrasound (as we have seen, this method can hardly be called infallible), but in some more reliable way. I answer: you can. In cases where the birth of a male or female child in the family is impossible for medical reasons (see above), sex determination is carried out early (7-10 weeks) using a chorionic biopsy. At the same time, a microscopic amount of its contents is taken from the uterus with a thin needle to determine the chromosome set of the fetus. In this case, the sex of the embryo is established with almost a 100% guarantee. However, it is not safe to carry out this procedure only to determine the sex of the unborn baby: a miscarriage may occur!

In conclusion, I want to remind dear dads and moms: it’s not you, not the doctor, and not the ultrasound that decides whether your family will be replenished with a boy or a girl. The main thing is from the very first days of conception to love a person who will enter life very soon, and even before his birth, to do everything possible to ensure that this life is for him or for her as happy as possible.

Sex choice – possible

American scientists have developed a method for separating spermatozoa containing the X chromosome (when such a spermatozoon fertilizes an egg, a female embryo is formed) from spermatozoa containing the Y chromosome (giving, respectively, a boy).

The method determines the amount of genetic material contained in cells. Y-chromosome spermatozoa contain approximately 2.8% less DNA than X-chromosome spermatozoa.

The procedure consists of several steps:

  1. DNA staining
  2. Sorting the sperm according to the amount of DNA
  3. Separating sperm with X chromosomes from sperm with Y chromosomes

The whole process is quite laborious: it takes a full day to process one sperm sample.

However, even this method cannot be called trouble-free. Moreover, it is interesting that the spermatozoa responsible for the conception of girls turned out to be “more obedient.” At the end of the described procedure, the X chromosome was contained in 85% of the spermatozoa in the experimental sperm sample. Boys, as usual, are more stubborn: the maximum content of male germ cells with Y chromosomes was only 65%.

The developed method is designed to help couples at risk of having a child with a genetic disease that selectively affects only people of a specific gender (only men or only women).

The editors of the journal do not know anything about specific cases of applying this – costly – method in Russia.

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