Sex-linked conditions are more common in men than in women because
A) men acquire two copies of the defective gene during fertilization.
B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed.
C) the sex chromosomes are more active in men than in women.
D) most genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness.

Question

Quizplus · Accepted Answer

Sex-linked conditions are caused by genes located on sex chromosomes, with the majority being on the X chromosome. Since men only inherit one X chromosome (from their mother), they only need to receive one copy of the recessive allele associated with the condition to be fully expressed. Women, on the other hand, have two X chromosomes and would need to inherit two copies of the recessive allele to be fully affected. Therefore, sex-linked conditions are more common in men than in women.

Sex-Linked Conditions Are More Common in Men Than in Women