In X-linked recessive traits, affected males are typically born to which type of mothers?

In X-linked recessive inheritance, affected males usually inherit the X chromosome carrying the recessive trait from their mothers. Given that males possess one X and one Y chromosome (XY), the presence of a single recessive allele on the X chromosome will result in the manifestation of the trait, as there is no corresponding allele on the Y chromosome that could mask it.

Mothers who are carriers have one normal X chromosome and one X chromosome with the recessive allele. When a carrier mother has a son, there is a 50% chance that the son will inherit the X chromosome with the recessive allele, leading to the expression of the trait. Affected mothers, on the other hand, would pass on a recessive allele on their single X chromosome to all their sons, ensuring they are affected.

While sons can also be born to unaffected mothers, this is only possible if the mother is a carrier; if the mother is completely unaffected and not a carrier, she would not have the allele to pass on to her son, and thus the son would not be affected. Therefore, the most accurate statement is that affected males are typically born to carrier mothers, as these mothers have the genetic disposition to pass on the recessive allele, leading to the possibility