Question

What is the genotype of a woman with hemophilia?

Answer 1

XhXh or homozygous recessive, sex-linked

Explanation:

A female with hemophilia would have to have her 2 sex chromosomes (the two X's), or pair 23, with the hemophilia alleles.

Those alleles cannot be the 'normal' or dominant allele (we'll call it 'H').
One H on the X chromosome would 'cover' up any recessive 'h' allele on the other chromosome homologue (her other X chromosome).

So, a female needs two recessive, or little 'h', alleles in order to express them. That means she cannot 'show' phenotypically as a hemophiliac unless BOTH alleles are present on those sex chromosomes.

That is why this disease is called sex-linked recessive, since it shows up on the X chromosome ( one of the sex chromosomes).