Answer:
The correct answer is - 1/2 or 50% for first and second child to be affected.
Step-by-step explanation:
Achondroplasia is an autosomal dominant disorder. Autosomal dominant disorder refers to the presence of a single copy of the defective gene that is enough to lead to dwarfness.
A cross of achondroplasia (Aa) parent to a person of normal height (aa) result in half of their children will be affected with dwarfism and the other half will be normal.
a cross between affected or dwarf and normal parent
Aa X aa
Punnett square:
a a
A Aa Aa
a aa aa
Aa- dwarfness
aa- normal height
The probability that both their first child and second child would have achondroplasia is
2/4 =1/2 or 50%.
