If a mother is Rh-negative and the father is Rh-positive, which statement is correct regarding their Rh-negative child?

In this scenario, understanding the inheritance of the Rh factor is crucial. The Rh factor is determined by the presence of the D antigen, with Rh-positive individuals either being homozygous (possessing two D alleles) or heterozygous (possessing one D allele and one d allele). Conversely, Rh-negative individuals lack the D antigen and must be homozygous for the d allele (dd).

Given that the mother is Rh-negative, she must have the genotype dd. The father, being Rh-positive, can have either the genotype DD (homozygous) or Dd (heterozygous). For their child to be Rh-negative, they must inherit one d allele from each parent, which can only occur if the father is at least heterozygous (Dd). If the father were homozygous DD, the child would inherit a D allele from him and would be Rh-positive.

Therefore, for the child to be Rh-negative, it is necessary that the father is heterozygous for the D allele. This makes the option referencing the father being heterozygous for D the most accurate statement regarding the inheritance of the Rh factor in this case.

The other options suggest incorrect genotypes for either the