The mechanism by which the sex of an individual is determined is called sex-determination. In human beings, sex of a newborn is genetically determined, whereas in some other it is not. There are 46 (23 pairs) chromosomes in human beings. Out of these, 44 (22 pairs) control the body characters and 2 (one pair) are known as sex chromosomes. The sex chromosomes are of two types- X chromosome and Y chromosome. At the time of fertilization, depending upon which type of male gamete fuses with the female gamete, the sex of the newborn child is decided.
If the gametes always have half the number of chromosomes, then how is the original number of chromosomes restored in the organism ?