The biological sex of a child, whether they are a boy or a girl, is determined by the chromosome contributed by the male parent.
Understanding Sex Chromosomes
Human cells typically have 23 pairs of chromosomes, totaling 46. One pair is known as the sex chromosomes, which determine an individual’s biological sex.
- Females: Have two X chromosomes (XX).
- Males: Have one X and one Y chromosome (XY).
The Role of the Parents
- Mother: Always contributes an X chromosome to the child.
- Father: Can contribute either an X or a Y chromosome.
Determining the Child's Sex
The specific chromosome the father contributes is what ultimately determines the child's sex:
- Father contributes an X chromosome: The child will inherit XX, resulting in a female offspring.
- Father contributes a Y chromosome: The child will inherit XY, resulting in a male offspring.
| Parent | Chromosome Contributed | Resulting Child's Sex |
|---|---|---|
| Mother | X | Female (XX) or Male (XY) |
| Father | X | Female (XX) |
| Father | Y | Male (XY) |
Summary
Therefore, it's the presence of the Y chromosome, and its origin from the male parent, that determines a child's biological sex as male. Without the Y chromosome, the child will be biologically female.
