Three Main steps for human sex determination & differentiation
1-At the genetic level at the time of gamete fertilization.
2- Differentiation of the gonads
3- Development of the internal & external genitalia in response to secretions from the differentiated gonads.
At the genetic level
Very early at the time of fertilization.
Male gamete united with female gamete.
If the sperm which fertilizes the ovum is carrying a Y- chromosome, the off spring will be a boy.
While if it is carrying Xchromosome it will be a girl (By the will of God).
The Holy Quran described these facts obviously, which were only known scientifically in the twentieth century.
That He did create in pairs, male and female, From a seed when lodged (in its place) (46:45) ( )
Does Man think that he will be left uncontrolled, (without purpose)?
Was he not a drop of sperm emitted (in lowly form)?
Then did he become a clinging clot; then did (Allah) make and fashion (him) in due proportion. ( )
And of it He made two sexes, male and female. Has not He, (the same), the power to give life to the dead? ( (40 39 )
The Gonadal sex The term sex determination refers to the development of gonadal sex. the process that occurs approximately 7 to 8 weeks gestation in the human fetus when either testis or ovary development occurs (Primary sex differentiation)
So the primary sex determination occurs when the premordial gonads(An organ in animals that produces gametes, especially a testis or ovary.)differentiate ` to either testes or ovaries.
The origin and time of formation of the gonads (primary sex differentiation) •Before the 7th week, no sex cords are seen in the gonads & it is impossible to differentiate morphologically between the male and female gonads, although the sex of the embryo is determined since the time of fertilization Hamilton Boyd & Mossman. Page 338, 400.
Of the embryo is a male the premordial germ cells carry XY sex chromosomes - A gene on the short arm of the Y-chromosome - called the testis - determining factor (TDF), stimulate the undifferentiated gonads into a testis.
The Prophet Mohammad (peace be upon him) said
When the Nutfa enters the womb and stays there forty nights ,God sends an angel to give it is formand creates its hearing , visual apparatus , skin , bone and flesh . Then he asks : O God , is it a boy or a girl ? And God determines whatever He decides . “ Narrated by Muslim (Kitab Al Qadar).
Now let man but think from what he is created! He is created from a drop emitted, (
Proceeding from between the backbone and the ribs: Surely (Allah) is able to bring him back (to life)! ( (8 7 )
The testis develops on the posterior abdominal wall opposite the first lumbar vertebra, later it descends to the scrotum pulling after it the testicular artery of the abdominal aorta.
The testis descends till it reaches the deep inguinal ring in the 3rd month.
The testis reaches the scrotum in the 8th month.
the ovary also develops on the posterior abdominal wall opposite the first lumbar vertebra. Descent of the ovary: The ovary reaches the false pelvis in 3rd month and the true pelvis shortly after birth. •As the ovary descends, it pulls the ovarian artery from the abdominal aorta.
The above mentioned Quaranic Ayes states clearly the site of formation of human gonads. The commentators of the Holy Quran differed in their explanation of this aye into two main groups. The first group includes the majority of the old commentators like Ibn Jarrir El Tabri, Ibn Kathir, Tafsir El Galalain who understood that the semen (male secretion) comes from the bones if the back and the female part comes from the ribs or breast.
Ibn El Qaiem refused this explanation. He stated that the word between means that the vertebral column & ribs lie in the same person either male or female (Ilam Al Mowoquin) volume 1/158.
Al Qurtobi, Al Oloosi, said that the Quaranic ayes are clear in indicating that both the male & female sexual gonads come from a place in between the bones of the back and the ribs.
It is important to notice that the nerve supply the blood supply and the lymph drainage remains in the whole life of the human individual connected to the area cited in the Holy Quran as between the vertebral column and the ribs.
The testicular artery comes from the abdominal aorta at the level of the second limber vertebra. The right testicular vein drains into the I.V.C while the left drains into the left renal veins.
The anatomical & embryological data greatly help in under standing the facts mentioned in Holy - Quran and the sayings of prophet Mohammed (peace be upon him).
These facts mentioned in Quran and Hadith precede the scientists by more than one thousand year. Prophet Mohammed (peace be upon him) mentioned since more than 1400 years very accurate statements.
At the sixth week the cloaca is subdivided by a septum into two parts: the urogenital and anal membranes. Mean while genital swellings become visible on each side of the urethral fold.
At the sixth week the cloaca is subdivided by a septum into two parts: the urogenital and anal membranes. Mean while genital swellings become visible on each side of the urethral fold.
By the end of the sixth week the external genitalia of both male and female are identical and it is impossible to distinguish between the two sexes (1).
The differentiation of the external genitalia starts after the sixth week. It goes on slowly so that by the twelfth week it becomes relatively easy to recognize the male from the female.
This again emphasizes the importance of the aforementioned hadith of the prophet Mohammed (peace be upon him) which was narrated by Muslin, whereby the angel enters the womb at 40th – 49 th day and asked
“O God, is it a boy or a girl and God determines whatever He decides”
Certainly the study of these Quranic ayes (verses) and the sayings of the prophet Mohammed (peace be upon him) in the light of scientific knowledge of modern science give a better understanding for these scriptures.
It is also clear that such pristine knowledge which was revealed fourteen centuries ago, was beyond the capacity of any mortal to group at that era.