Y-linked traits are genetic characteristics that are passed down through the Y chromosome, which is one of the two sex chromosomes in humans. These traits are typically found only in males, as they inherit the Y chromosome from their fathers. Examples of Y-linked traits include certain types of male infertility and specific physical features. Because Y-linked traits are directly linked to the Y chromosome, they cannot be inherited by females, who have two X chromosomes. This means that any traits associated with the Y chromosome will only be expressed in male offspring, making them unique to the male lineage.