2. Sex Determination

  • Sex determination is the process by which an organism's biological sex is established, primarily through genetics or environmental factors.
  • In humans, it's genetic, where the inheritance of an X and Y chromosome (XY) typically results in a male, and two X chromosomes (XX) results in a female. 
  • To understand how the determination of sex happens, we need to know the following process.
    1. Humans have 23 pairs of chromosomes. Out of these 23 pairs, 22 pairs are Autosomes and only one pair is the ‘Sex Chromosome’, which actively takes part in the process of sex determination.
    2. Both males and females carry two sets of sex chromosome.
    3. Male has one X and one Y (XY) sex chromosome in which both are active
    4. Female has both X (XX) sex chromosome in which one is active.
    5. The XY sex-determination system is found in humans, mammals, in some insects, and in few plant species.
    6. All children will inherit an X chromosome from their mother, despite whether they are a boy or girl. Thus, the sex of the children will be determined by the type of chromosome inherited from their father.
    7. A child who inherits Y chromosome will be a boy and who inherits X chromosome will be a girl.