Talmud: Niddah 31

Shalom Rabbi, A question of Niddah 31a and 31b:, A Rabbinical medical prescription to have only son’s and sons, etc. If the woman emits her seed first, she will bear a male child; if the man emits his seed first, she will bear a female child." Who wants female children?

Niddah 31a:24 to Niddah 31b: 1, “The sons of Leah, and it attributes the females to the males, in that Dinah is called: His daughter, it is derived that if the woman emits seed first she gives birth to a male, whereas if the man emits seed first, she bears a female. This statement is also derived from the following verse: “And the sons of Ulam were mighty men of valor, archers, and had many sons and sons’ sons” (I Chronicles 8:1-40). Is it in a person’s power to have many sons and sons’ sons?

I would appreciate your understanding of rabbinical medical advise. Reply