What is true about male sex-linked genes?

Male sex-linked genes are typically located on the X chromosome, and in males, who have only one X chromosome, only one copy of a gene is necessary to express traits associated with that gene. This means that if a male inherits a recessive allele for a trait on his X chromosome, he will express the phenotype associated with that allele because he does not have a second X chromosome to potentially carry a dominant allele that could mask the expression of the recessive one.

For instance, conditions like color blindness and hemophilia are examples of X-linked traits that manifest in males due to their single X chromosome. In contrast, females have two X chromosomes, so they generally require two copies of a recessive gene on both X chromosomes to express the same trait, leading to a difference in the expression of such traits between male and female offspring. Therefore, the understanding of sex-linked inheritance is crucial for comprehending how certain genetic traits are passed down through generations and why they may be more prevalent in one sex over the other.