The Prophet (saw) said: "After 42 nights of forming the zygote "nutfah" God sends an angel to it to shape (make its features), hearing, vision, skin, flesh, and after that the bones. ‘Oh God’, the angel asks, "male or female …"

 

Historical background

Embryology is a modern science that is mainly connected with the study of the development of human embryo, and only came to light a few decades ago. There had been some human attempts to understand the development of human embryos inside mothers' wombs in human history, but all, according to modern science, are proved to be incorrect.
 

The first study was made by Aristotle in the 4th century BC. He made theories according to some comparative observations that he made on birds; the final conclusion he reached, which was published in his book, was that the human embryo is formed from mixing the man's sperm with the monthly blood of women. This was incorrect information that found its way into the Bible.
 

Information about embryo development remained clouded with superstition till the end of the seventeenth century and the beginning of the eighteenth century, when the first microscope was invented.
 

Though still not sophisticated enough, this microscope gave us some good information about the development of cells on the human embryo. The staging of human embryos was not proposed until the 1942 by Streeter, and the stages as we know them now were not adopted worldwide until a few decades ago. (Keith Moor)

It should be noted that the scientific statements in the Prophetic Hadith and the Holy Qur’an give the crucial evidence to the truthfulness of the prophethood of Muhammad, and to the divine source of his message, especially for the generations that would live in the age of science. People at the time of the prophet were not concerned with these things simply because such things never occupied them, nor did they have the scientific method by which they could judge the Prophet's (saw) words about such scientific minute details.

The greatness of Islam is that it gives evidence to its divine source according to what humanity excelled in it.

Modern science supports the Prophet's hadith

"After 42 nights of forming the zygote "nutfah" God sends an angel to it to shape (make its features), hearing, vision, skin, flesh, and after that the bones. ‘Oh God’, the angel asks, "male or female …"

 So, according to the prophet's words, Prophet Muhammad (saw), by God's guidance, determined the period when a fetus takes its human form. According to the hadith, the point in time in which a fetus develops into a human shape is after forty-two days. Embryological observations, aided with scientific research, affirm that a human fetus can't be distinguished from other fetuses such as chicken, fish etc in the very early stages of fetus development or in other words all the fetuses of some animals are similar in the very early stages of development to the extent that we could not tell which is the human fetus if we compared all of them.
 

The Prophetic Hadith gives a special significance to the forty second day during a woman’s gestation; it can be understood that this day is a point in time that can divide the gestation period into two parts; the first of which is that period in which the human embryo has no human features, and the second is the period in which the human embryo acquires the human features.
 

It is now scientifically proven, that the embryo of a human and the embryos of some animals are of the same external shape, so that one can't tell which is which. Moreover, science defines the forty second day as the beginning of the embryo assuming the human features.

The embryological development

So according to this Hadith the human embryo has the same external features of some animal fetus and it is only after the first forty-two days that the human fetus begins to acquire the human physical appearances.
 

 Note that the hadith not only refers to shaping or modeling the fetus in human shape, but also refers to the development of the embryo's organs into its final stages, and shape after the forty-two days of gestation. The Prophetic Hadith refers to the completion of the eye, the completion of the ears, the skin, flesh and bones.  
 

It is scientifically proven that after the forty second day, the eyes move to the front of the face in their correct position, and the face acquires a human shape. Moreover, the eyes’ stalks that connected them to the brain begin to develop, and the retina becomes light sensitive, the cornea also begins to appear.
 

After the forty second day, the internal and external parts of the ear are created; its shape is extremely similar to that of the human being.

As for the limbs, though they start to make their appearance in the 4th week, they acquire the same shape of the humans'; they become longer, and the fingers and the toes which were not present before, become clearly defined after forty-two days.
 

 After the forty second day the skin separates into its layers, and we see the creation of the sweat glands. The functionality of the skin nerves also develops and the skin becomes sensitive to pain and temperature, which is evidence that points to innervations.
 

As for the bones, it is known that cartilaginous skeleton is formed then ossified in the seventh week; these bones are surrounded with muscles, which are referred to by the word “flesh” in the eighth week. The emergence of the stage of bones helps to straighten and smooth the embryo body.

Male or female?

Since the hadith talks about shaping the embryo into a human being, the part of the hadith which mentions "male or female,” will of course be connected with shaping the external organs for the embryo. It is scientifically established that the external genitalia are not clearly distinguishable as male or female until the 12th week. Since there is delay in the occurrence of the emerging of the male and the female organs, the Prophet (saw) used the word "Thoma" which implies a larger time passing than the word "and."