Question

Why do males only get haemophilia?

Answer 1

Haemophilia:

1. Haemophilia is a sex-linked chromosomal disorder.
2. It is an X-linked recessive disorder.
3. Males have only one X chromosome that they get from their mother so there are 50% chances of a male progeny being haemophilic if the mother is a carrier for the disease (heterozygous).
4. It is rare for females to have the disease because they have two X chromosomes, which they receive from their mother and father.
5. So for a daughter to be haemophilic, she should get two copies of defective genes.
6. The mother should be at least carrier and the father should be haemophilic.
7. Due to lack of treatment, haemophilic patients used to die before attaining adult age.