The the fertilized ovum, known as the zygote in modern embryology, is  a single entity in  the form of a germinal drop (nutfah), but it consists of mixtures of male and female gametes  (mingled fluid or  amshaj ). From a scientific point of view,  the term nutfah amshaj  , is entirely accurate as a plural adjective modifying the singular "nutfah", since it is a single entity consisting of multiple genetic mixtures from male and female gametes.

 

        The stage of  nutfah amshaj  (fertilized ovum) continues its development, maintaining the shape of the nutfah (i.e.drop ) ,  but dividing into smaller and smaller cells called blastomeres, until four days later it forms a spherical mass of cells known as a morula  .The morula remains free for 2 or 3 days  and on the 4th day after fertilization the morula then changes to a cystic structure called the  blastocyst and  the morula's cells separate into two parts  :

- inner cell mass: this is a collection of cells at one pole of blastocyst and projecting into its cavity , this part is responsible for the formation of the embryo.

- outer cell mass: these are the cells that form the frame of the blastocyst and consists of a single layer of flat cells , this part  is responsible for  absorption of nutritive fluids from uterine stroma , later this part shares in the formation of the placenta.

 

          The site of the blastocyst , where the inner cell mass is present , is called the embryonic pole , and the site opposite to it is called abembryonic pole . Although nutfah amshaj divides into smaller cells , it remains in the shape of a drop, in the size of the fertilized ovum due to the presence of the zona pellucida , a thick protective membrane that covers the fertilized ovum from outside and prevents its extension as it is inelastic .

 

            About the 5th day from fertilization , the zona pellucida ruptures exposing the sticky blastomeres , so the blastocyst becomes ready for implantation in the uterus. At this time ,  nutfah stage approaches its ends and become ready  to the next stage , alaqah .

 

The formation of Nutfah amshaj  results in the following important events ( Results of fertilization in modern embryology ) :

 

1. Al-khalq ( The creation):

         Al-khalq  , is the real beginning of the human being. Both  the sperm and the ovum carries 23 chromosomes that represents half of the chromosomes of any human cell. The sperm fuses with the ovum to form a new cell which carries a number of chromosomes that equals that carried by a human cell which is 46. This cell marks the beginning of a new human being, for the subsequent stages are determined by and based upon this step .

 

2. Al-Taqdir ( The genetic programming) :

         This a process in which the genetic material from the male and female are joined  to determine the characteristics of the embryo (dominant  and recessive), that represent  the characteristics of the ancestors and also of the future offspring of this embryo. This process takes place a few hours after Al-khalq  phase and modern embryology refer to this process as the genetic programming. The modern terminology is amazingly similar to the term taqdir , since taqdir means planning , determining and programming .  The Qura'n refers to these two successive events, i.e., al-khalq (creation) and al-taqdir (genetic programming), that occur at the early stages of the nutfah amshaj : chapter 80 (Abasa) ; verses 18 & 19 : " From what thing did He created him * From nutfah ( a drop of fluid ) He created him , then  immediately  planned (programmed ) him. ".  The Qura'n indicates that the process of taqdir follows the process of khalq in immediate succession , and it is  now known  in modern embryology that both processes are accomplished in less than 30 hours after fertilization .

 

3. Sex determination:

         The process of taqdir ( the genetic programming) that takes place in the nutfah amshaj involves the sex determination. In reference to this fact, the Qura'n states : chapter 53 (An-Najm) ; verses 45 & 46 : "And that He did create the two sexes ; the male and female * from nutfah when it is poured forth ”   , according to the previous verse , the nutfah that  is tumna  refers to nutfah ejected or poured into the uterus and that is only  applicable to male nutfah , that we previously described to indicate  the sperm,  that comes only from male , so male is the one  responsible for determination of the sex of the offspring . The scientific fact that male is responsible for sex determination has been reported in Qura'n since the 7th century  . It is well known now that , if the sperm that fertilizes the ovum bears a Y- chromosome , the embryo is male , but if it bears an X-chromosome , the embryo is female. However , this does not exclude sharing of both sexes in the determination of embryo sex .