Why are human females rarely haemophilic? Explain. How do haemophilic patients suffer?

Explanation

i) The gene for haemophilia is present on the X chxomosome, i.e., sex-linked.
ii) The disorder is due to a recessive mutant allele, hence a female with XX sex chromosomes, must be homozygous to produces the diseases.
iii) She must receive one of the defective alleles from her haemophilic father and the other X-chromosome with the defective allele from her mother, who is also haemephilic or at least a carrier haterozyous for the trait, `XX^(h)`.
The cross is a follows: