Colorblindness is another example of a sex-linked trait in humans. The abnormal gene dominates. What are some human sexlinked disorders, if some of these molecules are not present, the various colors in the spectrum can not be distinguished from each other, and the person is color-blind. The homozygote for a dominantly inherited abnormal gene may be equally affected with the heterozygote. Clearly, the likelihood of a recurrence would depend on whether a balanced form of the structural defect occurs in one of the parents.