Question

If a boy's father has haemophilia and mother is heterozygous, what is the chance that the boys will inherit haemophilia.

• A. $50\%$
• B. $25\%$
• C. $75\%$
• D. $100\%$

Answer 1

The correct option is A $50\%$

Father's chromosomes will be XhY whereas mother's chromosomes will be XhX (heterozygous). Their male offspring will have either XhY or XY chromosomes.Hence, there is a 50-50 chance of boy being haemophilic.

So, the correct answer is '50%'.