Question

Explain with the help of a flow chart that in human beings father is responsible for the sex (male or female) of the child.

Answer 1

Flow Chart of Father’s Role in Sex Determination:

Human Sex Determination

Females have two X chromosomes (XX) and produce eggs, each with an X chromosome. Males have an X and a Y chromosome (XY) and produce two sperm types:

• 50% of sperm contain an X chromosome
• 50% of sperm contain a Y chromosome

During fertilization:

• An X egg fertilized by X sperm results in a zygote with genotype XX, developing into a female child.
• An X egg fertilized by Y sperm results in a zygote with genotype XY, developing into a male child.

The mother always provides an X chromosome. The child's sex is determined by the chromosome (X or Y) carried by the father's sperm. 

Therefore, the father determines the child's sex.

Summary:

• Parental Contribution:
  • Mother (XX) → only X-type eggs
  • Father (XY) → 50% X sperm, 50% Y sperm
• Offspring Sex Determination:
  • X (egg) + X (sperm) → XX → Female
  • X (egg) + Y (sperm) → XY → Male
• Key Factor: Chromosome carried by the father's sperm