Having boys and girls has nothing to do with time, but with chromosomes. If the Y chromosome runs fast, it will combine with the egg; if it runs slowly, it will combine with X. It will be a girl. This knowledge has been learned in science class. Don't blindly think that having boys and girls is a woman's business, and it is related to men.

When did you decide to have boys and girls? To put it simply, it is to see which little tadpole swims fast and combine with the mother egg first.

I studied biology in high school. Man's chromosome 23 is XY, which produces two kinds of sperm, one is X chromosome and the other is Y chromosome. The female chromosome 23 is XX, which produces only one type of X egg cell.

Sperm and egg combine to form a fertilized egg, which develops into a baby. Therefore, if it is a fertilized egg combined with X chromosome sperm and egg cells, it is a girl; If it is a fertilized egg with Y chromosome sperm and egg cells, a boy will be born.

Therefore, it is really the man who has the final say in giving birth to boys and girls, to see which sperm is the first to combine with egg cells.

Is it decisive to have boys and girls at the moment of pregnancy? From the moment of fertilization, the gender has been determined.

Because men's sperm has only two types of XY, while women's sperm has only one type of Y, only XY together will be a boy, so from the moment when sperm and eggs combine, the gender has been decided.

There is no secret to having a boy and a girl. The sex of a child is determined by the moment when sperm and eggs meet. There is one kind of female egg and two kinds of male sperm, called X and Y. If X meets the egg, the pregnancy is a girl; if Y meets the egg, the pregnancy is a boy. See which sperm runs fast, and Sister Egg waits for Brother Sperm at the finish line to see which Brother Sperm reaches the finish line first! In fact, pregnancy is also a complicated process. Healthy sperm eggs are easy to get pregnant, and couples with unhealthy sperm eggs cannot even get pregnant!

Can IVF decide whether to have a boy or a girl? The sex of an embryo depends on whether the chromosome carried by the sperm is X or Y, and has nothing to do with the morphology of the sperm, so the sex of the embryo cannot be judged by its appearance.

For some gene carriers with sex chromosome (X or Y) genetic diseases, their offspring will have serious genetic defects. In this case, sex selection is allowed, that is, through the third generation of test tubes, embryo chromosomes are detected before embryo implantation, and embryos of a specific sex are selected for transplantation.

Therefore, couples who need IVF should consult professional doctors according to their own situation and choose the most suitable IVF method.