From "double single two children" to "single two children", from "comprehensive two children" to "comprehensive three children", in the past ten years, the mainland's fertility policy has been adjusted several times, gradually liberalized, and in 2021, the opening year of the "Fourteenth Five-Year Plan", it has entered a new stage. In the new year, those who have sons want to have a daughter, those who have daughters want to have a son, and every family wants to complete a "good"! However, there is a probability of giving birth to boys and girls, and today we will analyze it.
As we all know, every cell in the human body (including germ cells) has 23 pairs of chromosomes carrying genetic material, of which 22 pairs are autosomal, which determine all genetic information except sex, and the other pair is sex chromosomes, which determine the sex of the fetus. Autosomal male and female are the same, with no sex differences. Sex chromosomes are different, with 1 pair of sex chromosomes in men consisting of X and Y chromosomes (22+XY for males) and 1 pair of sex chromosomes for women (22+XX for females). Half of the 23 pairs of chromosomes came from the father and the other half from the mother.
Human cells multiply by meiosis, that is, 1 cell divides into 2, 2 and then divides into 4, so that it continues to divide. In the process of immature germ cells developing into mature germ cells, the chromosomes in the cells undergo a meiosis, that is, the mature sperm or egg cells contain only 23 chromosomes, which is half of the original, of which 22 are autosomal and 1 is sex chromosomes. 1 pair of sex chromosomes in men is XY, so after splitting and maturing sperm, one with X sex chromosomes is called X sperm, and the other with Y sex chromosome is called Y sperm. A woman's 1 pair of sex chromosomes is XX, so the eggs that split and mature contain 1 X sex chromosome. It can be seen that there are 2 kinds of male sperm and only 1 kind of female egg. So the birth of a male or female depends on the type of sperm cells in the male.
Many people will ask, what is the probability of having a boy and a girl?
Pregnancy International IVF experts explain that in theory it is male: female is 1:1 but in fact it is 1.12:1, if both sides have brothers and sisters in the family, then the next generation of all men is female, one man and two women The next generation is two men and one woman Very accurate. Whether it is a boy or a girl, or it is related to a certain probability of personal eating habits. If men drink less beer and the like, the probability of giving birth to a man will increase, especially men should pay special attention not to drink carbonated drinks such as Coca-Cola during their reproductive years, because these carbonated drinks can make the Y chromosome in male sperm lose vitality, thereby reducing the chance of having a boy.