The birth of a baby is a miracle of nature. It is the culmination of a complex process that begins with the fertilization of an egg by a sperm. This process results in the formation of a zygote, which is a single cell that contains all the genetic information necessary to create a new human being.

How cells divide

In order to grow and develop, the zygote must divide into two cells, then four cells, then eight cells, and so on. This process of cell division is called mitosis. During mitosis, the DNA in the cell nucleus is replicated, and then the cell divides into two identical cells.

How cells grow

As the zygote divides, it also grows in size. This growth is due to the process of cell growth. During cell growth, the cell increases in size by taking in nutrients from the environment.

How cells differentiate

As the zygote continues to divide and grow, the cells begin to differentiate. This means that they become specialized to perform different functions. For example, some cells will become skin cells, while others will become muscle cells, and still others will become brain cells.

The process of birth

After about 9 months, the baby is ready to be born. The process of birth is called labor. During labor, the cervix, which is the opening to the uterus, dilates to allow the baby to pass through. The baby is then pushed out of the uterus and into the vagina.


The birth of a baby is a remarkable event that is made possible by the complex and coordinated action of cells. From the fertilization of an egg to the delivery of a baby, cells work together to create a new life.

Additional information:

Here are some additional facts about how cells make babies:

  • The zygote divides about 50 times during the first 7 days of pregnancy.
  • By the end of the first trimester, the embryo has developed all of its major organs and systems.
  • The placenta is a temporary organ that provides the fetus with oxygen and nutrients from the mother’s blood.
  • Labor is typically divided into three stages: dilation, expulsion, and placental delivery.


  • Human Anatomy and Physiology: Sixth Edition, by Marieb and Hoehn
  • The Developing Human: Ninth Edition, by Moore and Persaud
  • Obstetrics and Gynecology: Fourth Edition, by Williams and Pritchard

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