Jermaine and Shikia are healthy parents of three young children.The oldest two,Bethany and Amber,are healthy,and they are six and four,respectively.Their youngest child,Roscoe,was born with Peeling Skin Syndrome two years ago.Roscoe's skin constantly peels,and is red and itchy.If Jermaine and Shikia have another child,the probability that he or she will inherit the skin condition is
A)1/8.
B)1/4.
C)1/3.
D)2/3.

Question

Quizplus · Accepted Answer

Peeling Skin Syndrome is a rare genetic disorder that follows a autosomal recessive pattern of inheritance. This means that for a child to inherit the disorder, both parents must be carriers of the gene mutation. 
Given that neither Jermaine nor Shikia have Peeling Skin Syndrome, but their child Roscoe does, it is likely that they are both carriers of the mutated gene. 
Therefore, if they were to have another child, there is a 25% chance that the child will inherit the mutated gene from each parent (as there is a 50% chance of inheriting one mutated gene from a carrier parent, and a 50% chance of inheriting a normal gene from the other parent). 
Multiplying these probabilities together gives us a 1/4 or 25% chance that the child will inherit Peeling Skin Syndrome.

Jermaine and Shikia Are Healthy Parents of Three Young Children