The continuation of the human race in the world is possible with the perfect working of the reproductive system. The bodies of men and women are quite different from each other in the functioning of their reproductive systems, but these functionally very different systems perfectly complement each other with the result that a new human being is born into the world. From basic elements produced in two distinct human bodies, independently of each other, one of the greatest wonders of the world occurs: the miracle of human creation...
In order for the miracle of human creation to happen, the necessary preparations actually begin many years earlier. First, male and female reproductive cells must become functional. This comes about in every human being through the process called puberty. The most important element in this process is certainly the hormonal system, which establishes communication among the cells under the direction of the brain.
God created a system in which all the needs of the human body and its development would be under the control of the brain. He caused messages coming to the brain from the organs to be evaluated by the brain, which then gives the appropriate response; this is then delivered to the required area in the shortest possible time. In this process the hormonal system is used to deliver the information. God has created in the human body a perfect postal route for communication. On this postal route, message-carrying molecules are called "hormones" each one of which really performs the function of a postman. Just as a postman follows his route throughout the city, delivering letters to the right addresses, so do hormones carry commands from the brain to the relevant cells. In this way, the functions required for human life are activated within the body.
But here we must be reminded that hormones are not human beings who possess the consciousness to know what messages to carry or to what place to carry them, or to determine the direction of their route. They have not received training, nor have they gained experience after years of studies. The hormones we have called the postmen, are composed of molecules that may be expressed in the most complex formulas. It is certainly a great wonder that a molecule knows where it is going and what it is delivering; that it determines what message it will take to which cell; that it finds its way without ever getting lost in the total darkness of a human body millions of times larger than itself and that it carries out this duty flawlessly, without damage to itself or to its message. This example alone is proof of the extraordinary systems that God has put in place within the human body.
It is He Who forms you in the womb however He wills. There is no god but Him, the Almighty, the All-Wise. (Qur'an, 3: 6)
The functioning of a person's hormonal system generally begins when he is still in his mother's womb and continues right up until his death. Reproductive glands start to function as a result of the effect of hormones too. But unlike other parts of the body, the secretion of hormones relevant to the reproductive glands begins in puberty. The hypothalamus, a small area at the base of the brain, is regarded as the controller of the hormonal system; in puberty, it begins to send messages to the pituitary gland to cause the reproductive organs to begin functioning.
Here too it is useful to point out another wonder. The hypothalamus is aware of the developments in the human body; for example, it knows how old a person is and whether or not the person is physically developed enough for his reproductive system to begin functioning. And the hypothalamus performs its work consciously. In other words, the hypothalamus, taking time into account and determining that a person's adulthood has come, gives the appropriate commands to the various endocrine glands in the body. It sends the messages (hormones) at exactly the right moment to the destined reproductive organs and assures the beginning of the development required to allow the human race to continue. And this does not apply to the hypothalamus of just one individual; at this moment the hypothalamuses of millions of people living in the world are performing this function in the same way and at almost the same period. The fact that this piece of flesh, occupying in our bodies a place no larger than that of a few sugar cubes, is aware of time and can make adjustments for the passage of time is certainly something that demands our thought and attention. How does the hypothalamus make such calculations? Has someone told the hypothalamus what it must do, or has it found out for itself? How does the hypothalamus calculate that the reproductive glands must develop in order for a human being to come into being? How does it know that this particular hormone must be secreted at this particular time? And how does it determine, among all the hormones that it produces, which one will set the reproductive system in operation at exactly the right time? Does it have the foresight to decide on some plan for the future, and make the requisite provisions and preparations to carry out this plan? Why does it wait until the exact time, neither sooner nor later, when the human body is physiologically ready for reproduction?
The intelligence that can make a mass of flesh without eyes, ears or even a brain, direct cells as if it were itself an intelligent being, is incomparable and too much for us to imagine.
It is neither chance nor any other force that makes the hypothalamus aware of time; the high intelligence that gives it its particular function belongs to God. It is the All-knowing God Who inspires this small piece of flesh to know what it has to do. That everything is in God's control is revealed in the verse:
... God is watchful over all things. (Qur'an, 33: 52)
In the pages that follow, it will be beneficial to keep this fact well in mind.