Haemophilia is more common in males because it is a

Options

A. recessive character carried by Y-chromosome
B. dominant character carried by Y-chromosome
C. dominant trait carried by X-chromosome
D. recessive trait carried by X-chromosome

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Hemophilia**: Hemophilia is a genetic disorder that affects the blood's ability to clot. This condition is primarily inherited and is more common in males than in females.

2. **Genetic Basis**: Hemophilia is classified as an X-linked recessive disorder. This means that the gene responsible for hemophilia is located on the X chromosome and that it is recessive.

3. **Inheritance Pattern**:
- Males have one X chromosome and one Y chromosome (XY), while females have two X chromosomes (XX).
- If a male inherits the X chromosome carrying the hemophilia gene, he will express the disorder because he does not have a second X chromosome to potentially carry a normal allele (the Y chromosome does not carry the hemophilia gene).

4. **Female Carriers**:
- Females can be carriers of the hemophilia gene if one of their X chromosomes carries the mutation while the other X chromosome is normal. In this case, they typically do not express the disorder because the normal allele can mask the effect of the recessive allele.
- A female would need to inherit the hemophilia gene on both of her X chromosomes (from both parents) to express the disorder.

5. **Conclusion**: Since males only have one X chromosome, they are more likely to express X-linked recessive disorders like hemophilia. In contrast, females have two X chromosomes, which provides a higher chance of having at least one normal allele to counteract the recessive trait.

**Final Answer**: Hemophilia is more common in males because it is an X-linked recessive disorder.

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