X-linked disorders are inherent disorders due to mutation in the X-chromosome which causes the phenotype to be always expressed in male and in female only in homozygous condition.

Colour blindness is a X-linked recessive disorder. In colour blindness, the affected individual is not able to distinguish colour especially red and green.

The son will always be colour blind if he has a colour blind mother.

Since the affected chromosome is X chromosome and not Y, the only female can be carriers in heterozygous condition.