Biology

Females can be carriers of X - linked recessive traits, but they are not always carriers. A female has two X chromosomes.
If she has a recessive allele for a particular X - linked trait on one of her X chromosomes and a dominant allele on the other X chromosome, she is a carrier.

However, if a female inherits the recessive allele on both of her X chromosomes, she will express the recessive trait.
For example, in the case of X - linked color...