Question

Describe the process of sex determination in human beings in detail.

Hint:

The sex of a human child is determined by the sperm cell, which carries either an X or Y chromosome. The egg always contributes an X chromosome.

Answer 1

Sex determination in human beings is controlled by the presence of sex chromosomes, which are a part of the human genetic makeup. In humans, the sex of an individual is determined at the moment of fertilization based on the combination of sex chromosomes inherited from the parents. The process involves the following steps:

1. The Chromosomes:
Humans have 23 pairs of chromosomes, one of which is the pair of sex chromosomes. These sex chromosomes can be either X or Y.
- Females have two X chromosomes (XX).
- Males have one X and one Y chromosome (XY).

2. The Role of the Sperm and Egg:
- The female egg always carries one X chromosome.
- The male sperm can carry either an X or a Y chromosome.

3. Fertilization:
At fertilization, the sperm (carrying either an X or Y chromosome) fuses with the egg (carrying an X chromosome). This combination results in one of the following possibilities:
- If the sperm carries an X chromosome, the resulting zygote will be XX, and the offspring will be female.
- If the sperm carries a Y chromosome, the resulting zygote will be XY, and the offspring will be male.

4. Determination of Sex:
The presence of the Y chromosome in males is responsible for male characteristics, including the development of testes and the production of male hormones (androgens). In the absence of a Y chromosome (XX combination), female characteristics develop, including the formation of ovaries and the production of female hormones (estrogens).

Conclusion:
The process of sex determination is genetically regulated by the sex chromosomes, where the father’s contribution determines the sex of the child. The combination of the X and Y chromosomes leads to the development of either male or female traits.