Ans.
Sex-linked genes are those genes that found on sex-chromosomes (X and Y chromosomes) and their phenotypic expression for a trait depends on the gender of the offspring.
Most of the sex-linked genes are present on X chromosomes as X chromosomes have more number of genes as they are made up of more DNA as compared to Y chromosome.
However, male individuals are more likely to exhibit the sex-linked traits. It is because most of the sex-linked traits are recessive and males have only one copy of X chromosome, while females have two copies of X chromosome. One mutated copy in male can exhibit the trait, while in females, both of the mutated copies are required to exhibit that trait.