The process of gender or sex determination of a baby is complex. But at the most simplified form it is the combination of the genetic materials from the mother and the father. The mother contributed its genetic material inside the egg, and the father likewise also contribute the genetic material in the sperm. It is the combination of the genetic material genetic materials from the egg and the sperm in a process, called fertilization that combine those together to form, the basic foundation for the building of a creation of a being. Within the egg there are genes consisted of DNA which are packaged together into chromosomes. The egg contains 23 chromosomes. The sperm also contains 23 chromosomes.   within the egg or the sperm exists 1 unique chromosome out of those 23 called the sex chromosome. The sex chromosome of the egg is called an X chromosome while the sex chromosome of the sperm can be an x or a Y chromosome. The X chromosome will encode for a girl while the Y chromosome will encode for a boy. Therefore if a sperm has a X sex chromosome then when combined with the X chromosome of the egg..a baby girl will result..however if the sperm has a Y sex chromosome then when combined with the X chromosome of the egg..the result will be a bit. So ultimately the sperm which if contains the Y or X chromosome will determine the sex or gender of a child.
