Sex of the Baby: The Science and the Truth
For parents-to-be, while looking forward to the healthy growth of their baby, they will inevitably wonder whether the little one in their tummy is a boy or a girl. So what determines the sex of a baby? Today, let’s delve deeper and unravel the mystery of your baby’s gender.
Chromosomal Mechanisms that Determine Sex
Human sex is determined by the XY sex chromosomes. Each body cell contains 23 pairs of chromosomes, of which 22 pairs are autosomes and the 23rd pair is the sex chromosome, which plays a key role in sex determination. The female sex chromosomes are homozygous, denoted by XX, while the male sex chromosomes are heterozygous, denoted by XY. The egg and sperm contain only half the number of chromosomes each, so the egg produced by a woman has a fixed chromosome form of 22+X, whereas the sperm produced by a man has two forms, 22+X and 22+Y respectively. When the egg is fertilised, it is reassembled into a new individual with 23 pairs of chromosomes, and it is completely random as to which sperm will unite with the egg. If a sperm with an X sex chromosome combines with the egg, the baby will develop into a girl; if a sperm with a Y sex chromosome combines with the egg, the baby will develop into a boy. Thus, the sex of the baby is actually determined by the sex chromosome carried by the sperm that fertilises the egg, which means that the father’s sperm plays a decisive role.
Exploring the feasibility of human intervention in the sex of the baby
In folklore, there are many ‘biased recipes’ that claim to determine the sex of a baby, such as ‘sour children’ and ‘changing the acidity or alkalinity of the internal environment’. But can these really intervene in the sex of the baby?
Sour Children and Hot Women
The saying that ‘sour children are hot and spicy’ has been around for a long time. Especially in some places, if a pregnant woman at home likes to eat sour food after pregnancy, her family will be very happy; if she likes to eat spicy food, her attitude may be different, and some elders may even ask the pregnant woman to eat more ‘sour food’. But in fact, after pregnancy, due to changes in hormone levels in the body, stomach acid secretion is reduced, there will be a decrease in appetite, sensitivity to odour, acidophilic or spicy and so on, and even want to eat food that you usually don’t like, which are normal physiological responses to pregnancy, and the sex of the foetus has no correlation.
Changing the pH of the female vagina
There is also a theory that changing the pH of a woman’s vagina before sex can control the birth of a boy or a girl. For example, if you want to have a boy, you can use a low concentration of baking soda to rinse the vagina; if you want to have a girl, you can use a certain concentration of vinegar to rinse the vagina. However, this method has no scientific basis. Women’s vaginas have the ability to balance their own acidity and alkalinity, and disrupting this balance will not only fail to control the sex of the foetus, but will also easily lead to gynaecological disorders, so it is not recommended for women to try this.
When to know the sex of your baby and the rules
Generally speaking, the sex of the foetus can be observed through ultrasound at around 4 months of pregnancy, when the sex characteristics of the foetus can be identified with the naked eye. In addition to the traditional ultrasound, pre-implantation genetic diagnosis, chorionic villus testing and amniotic fluid testing can also identify the chromosome type and thus the sex of the foetus. However, it is important to stress that in China, the unauthorised use of all methods of foetal sex testing is expressly prohibited. Only in some special cases, such as when there is a sex chromosome-linked genetic disease (e.g., colour blindness), it may be necessary to identify the sex of the foetus in order to reduce the risk of the disease occurring. Among the current assisted reproductive technologies, the more advanced third-generation IVF technology, although it is technically possible to detect the sex of the embryo, the technology is mainly for the purpose of eugenics, and is used to screen out embryos with genetic disorders, in order to maximise the protection of the health of implanted embryos.
Lastly, I hope all prospective parents will understand that the sex of the baby is a natural random result, which we can neither choose nor need to choose, and the health of the baby is the most important.