Wyjścia 1:16 Midrasz: Shemot Rabbah, Midrash Tanchuma, Midrash Tanchuma Buber & Mekhilta DeRabbi Yishmael

He said: When you deliver the Hebrew women and you look upon the birthstool [ovnayim], if it is a son you shall kill him but if it is a daughter she shall live (Exodus 1:16).
“He said: When you deliver the Hebrew women…” Why did he command to kill them by means of the midwives? It was so the Holy One blessed be He would not prosecute him, but would punish them.
“And you look upon the ovnayim,” [this is] the place through which the baby passes [as it emerges]. Alternatively, ovnayim, Rabbi Yehuda bar Simon said: The Holy One blessed be He makes a woman’s limbs hard as stones [avanim] when she is sitting on the birthstool in childbirth, as were it not so, she would die. Rabbi Pinḥas the ḥaver says in the name of Rabbi Yona, this supports Rabbi Yehuda bar Simon: Ovnayim means nothing other than a block, which is a hard object, as it is written: “I went down to the potter’s house, and behold, he was at work on the wheel [ovnayim]” (Jeremiah 18:3).³⁰This is the surface on which the potter produces his vessel.. Rabbi Ḥanin said: He provided them a clear sign: Just as the potter has one thigh here and one thigh there and the block in the middle, so too, a woman giving birth has one thigh here and one thigh there and the newborn is in the middle. Some say: When she crouches to deliver, her thighs grow cold as stones.
“If it is a son, you shall kill him.” He said to them, if it is male, kill him, and if it is female, do not kill her; rather, if she lives, she lives, and if she dies, she dies. They said to him: How will we know if it is male or if it is female? Rabbi Ḥanina said: He provided them a clear sign. If it is face down, know that he is male, as he is looking, in his mother, at the earth from which he was created. If it is face up, she is a female, as she is looking at her source, the rib, as it is stated: “He took one of his ribs” (Genesis 2:21).
The Holy One blessed be He said to him: ‘Wicked one, whoever gave this counsel is a fool. You should have killed the females. If there are no females from where will the males marry women? One woman cannot take two men, but one man can take ten women, or one hundred.’ That is: “The princes of Tzoan are but fools” (Isaiah 19:11); it is they who gave him this counsel.

Another interpretation (of Lev. 12:2), “When a woman emits her seed [and bears a male]”: If the woman comes first, she bears a male; if the man comes first, [she bears] a female.⁸Ber. 60a; Nid. 31ab; see above, Tanh. (Buber), Gen. 8:18; cf. Sifra to Lev. 22:1-9, (217: Emor, Parashah 4). R. Abbin the Levite said, “The text has given you a clue (in vs. 5), ‘If she bears a female’ (with no mention of her giving her seed). If the man comes first, a female is produced; [if] the woman comes first, a male is produced. Thus it is stated (in vs. 2), ‘When a woman emits her seed and bears a male.’” R. Hiyya bar Abba said, “Therefore, the male is dependent (for his procreation) upon the woman; and the female, upon the man. Thus it is stated (in Gen. 22:20-23), ‘Behold Milcah, she also has borne sons to your brother Nahor, Uz his first-born and Buz his brother…. And Bethuel brought forth Rebekah.’ It also says (in I Chron. 2:48-49), ‘Maacah, the concubine of Caleb bore [Sheber] and Tirhanah. She also bore Shaaph the father of Madmannah, Sheva the father of Machbenah and the father of Gibea. And the daughter of Caleb] was Achsah.’ Thus females are dependent (for procreation) upon the man; and the males, upon the woman. It is therefore stated (in Lev. 12:2), ‘When a woman emits her seed.’” R. Ayyevu said, “The Holy One, blessed be He, performs a miraculous act with a person. When a person is put in a hot water for [only] a single day, is not his life struggling [to survive] because of it? But when an infant is put in its mother's belly for nine months,⁹According to Lev. R. 14:3, a woman’s womb is at boiling temperature. the Holy One, blessed be He, protects it.” Our masters have said, “The Holy One, blessed be He, has performed a miraculous act with this person. When the person is put in a bath tub¹⁰Gk.: embate. for one day, does not his life fail because of it? But when the infant is put in its mother's womb for nine months, its life does not fail because of it. Why? Because the Holy One, blessed be He, is performing a miraculous act with it (i.e., with the infant).” Job said (in Job 36:3), “I will fetch (‘S’) my knowledge from afar.” Now Job saw people, with a woman ('shh) giving birth to a man,¹¹‘ShH and ‘S’ are more alike in Hebrew than the transliterations show. In the unpointed text S (sin) and Sh (shin) are the same letter. Also a final H (he) sounds so much like a final ‘(alef) that Rabbinic Hebrew sometimes conflates the two. Thus the midrash understands Job 36:3 to mean that the WOMAN in Lev. 12:2 was Job’s KNOWLEDGE FROM AFAR. and also the ship (of Prov. 31:14) sails in the midst of the waters inch by inch.¹²The image suggests Prov. 31:14, according to which the heroic wife is LIKE MERCHANT SHIPS; SHE BRINGS HER FOOD FROM AFAR. So Enoch Zundel in his commentary, ‘Ets Yosef, here on Tanh., Lev. 4:3. Now he was surprised over these things and said (in Job 36:3), “I (like the woman of Prov. 31:14) will fetch my knowledge from afar.” R. Judah [bar Simon] said, “A woman's two haunches become like two haunches of stone, in order that she may have strength when she gives birth. As thus it is stated (in Exod. 1:16), ‘look at the birthstool (literally, the pair of stones).’” R. Meir said, “The Holy One, blessed be He, performs a miraculous act with the infant. How? Before the woman bears, she retains blood; after she gives birth, the blood departs to the breasts and becomes milk. Then the infant nurses on them.” R. Abba bar Kahana said, “The Holy One, blessed be He, performs a miraculous act with the infant. How? When the funda (i.e., pouch)¹³The Latin word means “moneybag”. is full with its mouth down, the coins are scattered; but the woman has her funda [with its opening] down, and the fetus is retained.” Another interpretation: An animal walks about with the fetus in the midst of its belly; but a woman walks about erect with the fetus in the midst of her belly, and the Holy One, blessed be He, preserves it.

R. Aha and our sages discussed this verse. Our sages said: He repeated this twice to himself and then He told it to Israel, as it is said: Then did He see it and declare it. This refers to the first time, while He established it, yea, and searched it out alludes to the second time. And after that is written: and unto man He said, etc. R. Aha, however, contended that He considered the matter by Himself four times and then told it to Israel, as it is said: Then did he see it and declare it; He established it, yea, and searched it out, and after that is written: And unto man He said. From whom do you learn this? From Jochebed and Miriam, about whom it is written: And the king of Egypt called for the midwives, and said unto them … ye shall look upon the birthstool; if it be a son (Exod. 1:15–16). Why were they commanded to do that? Because the astrologers had told him: “The redeemer of Israel will be born on that day, but we do not know whether he will be born to an Egyptian woman or an Israelite.” At the time he assembled every Egyptian and said to them: “Loan me your sons for a day,” as is said: Every son that is born ye shall cast (ibid., v. 22). It does not say “every child of an Israelite” but rather: Every son that is born, whether Egyptian or Israelite, ye shall cast into the river.