Answer:
"They may be on one sex chromosome and not the other" is true of sex-linked genes.
Step-by-step explanation:
Gender related is a function in which a gene is found on a sex chromosome. It is because the X chromosome is wide and includes a lot more genes than the shorter Y chromosome. In a sex-linked disorder, males are typically affected, because they have a single xerox of the X chromosome that contains the mutation. Prominent examples of sex-related genes in human beings are those that code for colorblindness, or those that code for hemophilia i.e incapacity to make blood clots.