Question

A man possesses an allele for a recessive X-linked genetic condition, and his wife does not possess the allele. What are the odds that the couple’s son will express the condition?
100%
25%
50%
0%

Answer 1

The odds that the couple's son will express the condition is 50%. Since the man possesses the allele for the recessive X-linked condition, he can only pass on that allele to his daughters. Therefore, all sons of the couple will inherit the normal allele from their mother and will not express the condition. However, the sons will have a 50% chance of being carriers of the allele.