Inheritance of hemophilia in European royalty

A pedigree for the X-linked recessive condition hemophilia in the royal families of Europe. A recessive allele causing hemophilia (failure of blood clotting) arose through mutation in the reproductive cells of Queen Victoria or one of her parents. This hemophilia allele spread into other royal families by intermarriage. (a) This partial pedigree shows affected males and carrier females (heterozygotes). Most spouses marrying into the families have been omitted from the pedigree for simplicity. Can you deduce the likelihood of the present British royal family’s harboring the recessive allele? (b) A painting showing Queen Victoria surrounded by her numerous descendants.