Question

Haemophilic man marries a normal woman. Their offspring will be

• A. all haemophilic
• B. all boys haemophilic
• C. all girls haemophilic
• D. all girls are carriers

Answer 1

The correct option is D all girls are carriers

The genotype representation of a haemophilic male is X${}^h$Y and the normal female would have a genotype of XX. Females have two X chromosomes. When the allele is present on one of the X chromosome, the female is said to possess the trait but doesn’t show phenotype expression. Such females are known as carriers and lead a normal life. Their genotype is represented by (X${}^h$X or XX${}^h$). But when both the X chromosomes have a mutated allele, the female is said to be haemophilic. Their genotype is represented by X${}^h$X${}^h$.
The following cross depicts the offsprings of a haemophilic man married to a normal woman.
Both the female children are carriers, so they will not be diseased, though they possesses the allele. The male children are normal.