For expectant mothers and fathers-to-be, while looking forward to the healthy growth of the baby in the belly, they must be wondering what factors determine the sex of the baby? Can I choose to have a boy or a girl?
How does the sex of the fetus develop?
In general, we distinguish between male and female sexes based on the external genitalia of newborns. In fact, the real difference between men and women is doomed at the moment when the egg and sperm are combined. So how is gender determined?
It is well known that eggs and sperm have only half of their chromosomes. The union of the egg to the sperm, or fertilization, is recombined into a new individual with 23 pairs of chromosomes. Who decides to give birth to boys and girls? It is the sex chromosome --- that determines the development of the baby's sex.
And eggs can only provide X sex chromosomes, but what about sperm? It carries both the X chromosome and the Y chromosome, which is the key factor in determining the sex of the baby. Therefore, the sex of the baby is determined by the lucky sperm that drilled into the egg. If this lucky little guy has an X chromosome, the baby is a girl; if it has the Y chromosome, the baby is a boy.
In fact, the difference between sexes is not only the external genitalia we see, but also the gonads (ovaries or testicles), reproductive ducts (fallopian tubes, uterus or vas deferens, etc.). The primary reproductive glands are first formed when the baby is 5 to 6 weeks old. At this point, the primitive gonads can develop both in the direction of the ovaries and towards the testicles. When the baby grows to the 8th week, if there is a Y chromosome, under the action of the testicular determinants on the Y chromosome, the gonads develop in the direction of the testicles, that is, the male; if there is no Y chromosome, it develops in the direction of the ovaries and becomes a baby girl.
The original reproductive duct also had two pairs, one for the middle renal tube, the basis of the male reproductive duct, and the other is the para-middle renal duct, which is the basis of the female reproductive duct.
If it is a male baby, the testicles will produce testosterone, which promotes the development of the baby's middle kidney tube into the epididymis, vasectomy tube and seminal vesicles; it also inhibits the development of the paranormal kidney tube, so that the reproductive duct differentiates into men.
If it is a baby girl, due to the absence of testosterone, the middle renal canal degenerates, the paranormal renal tube develops, and the uterus and fallopian tubes form at the 12th weekend of the baby's development. External reproduction develops slightly later and is also affected by the gonads. Under the action of testosterone, "chicks" are formed; conversely, they become girls. It can be seen that the formation of females is the natural law of embryonic development, and to become a baby boy requires the continuous efforts of the Y chromosome.
And the sex difference that we can recognize with the naked eye is the external genitalia. The first difference between a male and female baby is at 12 weeks; by 16 weeks, the sex of the fetus can be determined by the external genitalia. However, if you want to know your baby's gender through noninvasive methods, it may be a little later.
After about 20 weeks, the baby's gender can be preliminarily determined by non-invasive measures such as ultrasound. In some special cases, diseases that accompany sex chromosome inheritance, such as color blindness, etc., may need to reduce the occurrence of diseases through sex identification, and may not need to wait until 20 weeks later, which can be achieved early through science and technology. Commonly used such as pre-implant genetic diagnosis, villous tissue, amniotic fluid detection, etc., but most of the techniques are traumatic, may affect the health of expectant mothers and babies, and are generally not recommended.
Is it possible to artificially decide to have a boy or a girl?
There are many opinions about the factors that affect the birth of boys and girls, but the most common theory is that acid-base constitution affects the sex of children. In the alkaline environment, sperm containing the "Y" chromosome are more active, easy to give priority to fertilization, and form baby boys, so some people think that eating more alkaline foods can increase the probability of having a baby boy. In the same way, some people think that rinsing the vagina with an alkaline solution such as soda water is also beneficial to having a baby boy by changing the pH of the vagina.
In addition, there are other theories, such as men engaged in high-energy-consuming work or exercise, too much acidic metabolism accumulated in muscles and body fluids, which can affect the vitality of sperm containing "Y" chromosomes, thereby reducing the probability of having a baby boy, and so on.
There are many talks about giving birth to boys and girls, basically revolving around changes in the acidic and alkaline environment. Although there is scientific evidence that the "Y" chromosome is more likely to survive in an alkaline environment, its difference is very weak, and it is very difficult to manipulate the sex of a child through this. What's more, in order to maintain normal physiological activities, the human body has the ability to automatically regulate the acid-base balance in the body.
From a female health perspective, the normal vaginal flora maintains an acidic environment to inhibit the growth of pathogens, known as vaginal self-purification. Arbitrarily changing the acidity and alkalinity of the vagina will cause women to suffer from diseases such as vaginitis, and even affect pregnancy.
With the development of medical research, people can currently identify the type of chromosome after special technical treatment by biopsying some cells on the embryo, taking villus cells or extracting amniotic fluid from amniocentesis before, first and second trimesters. But these technologies are only applicable to people with genetic diseases, and the vast majority of countries, including China, strictly prohibit sex selection for non-therapeutic purposes.
The purpose of developing these technologies is not to cater to people's wishes to have boys and girls, but to consider eugenics. The incidence is high in boys because certain diseases, such as hemophilia and pseudo-hypertrophic large progressive muscular dystrophy, have a high incidence in boys because genes are on the "X" chromosome, while men have only one "X" chromosome. In view of the fact that these diseases seriously endanger people's health, the occurrence of these genetic diseases can be reduced by selecting female embryos for transfer into the womb before pregnancy through pre-implant genetic diagnostic techniques.
In real life, although the probability of having a boy and a girl is not absolutely one-to-one, it is generally equal, which is a natural law. Both boys and girls are the best gifts that nature has given to human beings, and human intervention in infant sex decisions violates both the law and the balance of nature.
We should remember that we can't choose the sex of the baby, we don't have to choose, naturally it is the best.