Why is hemophilia more common in males than females?

Hemophilia is an inherited genetic disorder caused by a deficiency or abnormality in specific clotting proteins in the blood. The defective genes responsible for hemophilia are located on the X chromosome. Since males have one X chromosome and one Y chromosome, while females have two X chromosomes, the inheritance pattern of hemophilia is different in both genders.

Reasons for Hemophilia Being More Common in Males:

1. X-Linked Inheritance: The genes for clotting factors VIII and IX, which are essential for blood clotting, are located on the X chromosome. Therefore, hemophilia is an X-linked recessive disorder.

2. Carrier Females: When a female carries one copy of the defective gene for hemophilia on one of her X chromosomes, she is called a carrier. Carrier females usually have normal blood clotting function but can pass the defective gene to their children.

3. Affected Males: Males, on the other hand, have only one X chromosome and one Y chromosome. If they inherit a single copy of the defective gene from their mother (carrier) or have a mutation in their own X chromosome, they will be affected with hemophilia.

4. Absence of Second X-Chromosome: Unlike females who have two X chromosomes, males do not have a second X-chromosome to compensate for the defective clotting gene. This means that even if they carry a single copy of the defective gene, they will manifest the disorder.

5. Genetic Probability: Statistically, males have a 50% chance of inheriting the defective gene from a carrier mother, leading to a higher prevalence of hemophilia in males compared to females.

It's important to note that while hemophilia is more common in males, females can also be affected if they inherit two copies of the defective gene (one from each parent). However, female hemophilia cases are much rarer because of the requirement for the presence of two affected gene copies.