Who does sex determination?

Sex determination in humans is a biological process controlled by chromosomes. Every human cell contains 23 pairs of chromosomes, including one pair of sex chromosomes that determine whether a person is male or female.

Key Points

• ​Sex determination is carried out by the Y chromosome. Males have XY chromosomes, while females have XX chromosomes.
• The sperm from the father carries either an X or a Y chromosome, while the egg from the mother always carries an X chromosome.
• If the sperm carries an X chromosome, the baby will have an XX combination and be female.
• If the sperm carries a Y chromosome, the baby will have an XY combination and be male.
• Since the presence of the Y chromosome is responsible for triggering male development, it plays a decisive role in sex determination.

Thus, it is concluded that Y Chromosome determines sex determination.

Hint

• The X chromosome alone does not determine sex because both males and females have at least one X chromosome.
• XY chromosomes represent the male genetic makeup, but the Y chromosome specifically determines maleness.
• XX chromosomes indicate a female, but they do not determine sex—the father’s sperm (carrying either X or Y) does.