The Y-chromosome is one of the two sex chromosomes in humans, the other being the X-chromosome. It is typically found in males, who have one Y-chromosome and one X-chromosome, while females have two X-chromosomes. The Y-chromosome carries genes that are crucial for male sex determination and the development of male reproductive organs. In addition to its role in sex determination, the Y-chromosome is also used in genetic studies and ancestry tracing. It is passed down from father to son, making it a valuable tool for studying lineage and understanding human evolution. The presence of the Y-chromosome is a key factor in identifying male individuals in various biological and forensic contexts.