The Prophet (ﷺ) said, "At every womb Allah appoints an angel who says, 'O Lord! A drop of semen, O Lord! A clot. O Lord! A little lump of flesh." Then if Allah wishes (to complete) its creation, the angel asks, (O Lord!) Will it be a male or female, a wretched or a blessed, and how much will his provision be? And what will his age be?' So all that is written while the child is still in the mother's womb."

The Prophet (ﷺ) said, "Allah has appointed an angel in the womb, and the angel says, 'O Lord! A drop of discharge (i.e. of semen), O Lord! a clot, O Lord! a piece of flesh.' And then, if Allah wishes to complete the child's creation, the angel will say. 'O Lord! A male or a female? O Lord! wretched or blessed (in religion)? What will his livelihood be? What will his age be?' The angel writes all this while the child is in the womb of its mother."

I visited Abu Sariha Hudhaifa b. Usaid al-Ghifari who said: I listened with these two ears of mine Allahs Messenger (ﷺ) as saying: The semen stays in the womb for forty nights, then the angel, gives it a shape. Zubair said: I think that he said: One who fashions that and decides whether he would be male or female. Then he (the angel) says: Would his limbs be full or imperfect? And then the Lord makes thein full and perfect or otherwise as He desires. Then he says: My Lord, what about his livelihood, and his death and what about his disposition? And then the Lord decides about his misfortune and fortune.

"A man from among the Ansar came to the Prophet (ﷺ) and said: 'O Messenger of Allah (ﷺ), I have a slave girl. Should I do 'Azl (coitus interruptus) with her?' He said 'Whatever is decreed for her shall come to her." He (the Ansari) came to him later on and said: "The slave girl has become pregnant." The Prophet (ﷺ) said: "Nothing is decreed for a person but it will surely come to pass."

"My wife is breast-feeding and I do not want her to get pregnant." The Prophet said: "What has been decreed in the womb will come to be."