Which is characteristic of X-linked recessive inheritance?

ANS: B
In X-linked recessive disorders, the affected individuals are usually male. With recessive traits, usually two copies of the gene are needed to produce the effect. Because the male only has one X chromosome, the effect is visible with only one copy of the gene. Females are usually only carriers of X-linked recessive disorders. The X chromosome that does not have the recessive gene will produce the normal protein, so the woman will not show evidence of the disorder. The transmission is from mother to son. Usually the mother and father are unaffected.