A disease passed on to 50% of male offspring has what type of inheritance pattern?

The correct answer is that the disease pattern described indicates X-linked recessive inheritance. In X-linked recessive disorders, the gene responsible for the disease is located on the X chromosome. Since males have only one X chromosome (paired with one Y chromosome), if a male inherits the affected X chromosome from his mother, he will express the disease because there is no corresponding allele on his Y chromosome to counteract it. This results in 50% of male offspring being affected if the mother is a carrier (heterozygous) for the condition.

On the other hand, females have two X chromosomes, so they can be carriers (heterozygous) without expressing the disease if they inherit one normal X chromosome alongside one affected X chromosome. As a result, the inheritance pattern described—where 50% of male offspring are affected—fits perfectly with X-linked recessive transmission.

The other inheritance patterns do not support this scenario as effectively. In autosomal recessive conditions, both males and females are affected equally if they inherit two affected alleles, leading to a different risk for male offspring. Autosomal dominant conditions would result in affected individuals in each generation among both genders, and X-linked dominant conditions would typically lead to affected females passing the condition to