Hemophilia is a sex-linked recessive disorder. If a carrier female ($X^H X^h$) has children with a normal male ($X^H Y$), what is the probability that a son will have hemophilia?
0%
25%
50%
100%
📝 Detailed explanation
A son inherits the Y chromosome from the father and either $X^H$ (normal) or $X^h$ (hemophilia) from the mother. Thus, there is a 50% chance a son is affected.
