Is it possible for any son of a couple formed by a hemophilic man (XhY) and a nonhemophilic noncarrier (XX) woman to be hemophilic?
If mothers are not affected by the disease and noncarriers of the gene (do not have an Xh allele) it is impossible for their sons to be hemophilic since the X chromosome of males always comes from the mother. Hemophilic sons are only possible when the mother is hemophilic (homozygous for the hemophilic gene, a very rare situation) or carriers of an affected X chromosome (XXh).
