Hemophilia is an X-linked recessive condition in which blood does not clot properly. Queen Victoria of England had one allele for hemophilia. Most of her male descendants had the disorder, but few females had it. Why did hemophilia occur more frequently in Queen Victoria’s male descendants?

Because hemophilia is an X-linked recessive condition.

Explanation:

As the problem states, hemophilia is an X-linked recessive condition.

Meaning that in Queen Victoria's female descendants (coded XX) which inherited the Queen's one allele, for hemophilia to appear in them it would be necessary to inherit another hemophillia-carrying allele from the father.The Queen's male descendants (coded XY) would always manifest hemophilia if they inherited the Queen's hemophilia allele, as they possesed only one X gene.