After giving birth to a daughter, the doctor said that a second child will give birth to a son, right?

First of all, you should understand that doctors are not "fortune tellers".

What makes him say that "the second child will have a son" and "the second child will have a son"? If the doctor really tells you so, it can only be said that the doctor is not far from the "quack".

It has been proved by medicine that only when the accidental Y of the male sex chromosome is combined with the X egg of the female sex chromosome can a boy be successfully born, and vice versa.

Look at the problem of having boys and girls scientifically. The chances of getting pregnant with a boy or a girl are 50-50. Let nature take its course, anything "deliberate" will often "fail".

I hope my answer will make you feel something.