Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming haemophilic extremely rare ? Explain.

Explanation

### Step-by-Step Solution:

1. **Understanding Hemophilia**:
- Hemophilia is a genetic disorder that affects the blood's ability to clot. It is primarily inherited in a sex-linked manner, specifically linked to the X chromosome.

2. **Sex-Linked Inheritance**:
- Hemophilia is caused by a mutation in a gene on the X chromosome. Since males have one X and one Y chromosome (XY), they are more likely to express the disorder if they inherit the affected X chromosome (X^H). Females have two X chromosomes (XX), so they can be carriers (X^H X) or affected (X^H X^H).

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