The XY chromosome system is a method of determining biological sex in many organisms, including humans. In this system, individuals typically have two sex chromosomes: males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The presence of the Y chromosome is crucial for male development. The Y chromosome carries genes that are important for male sex determination and spermatogenesis. It is significantly smaller than the X chromosome and contains fewer genes. The X chromosome, on the other hand, carries a wide range of genes that are essential for various bodily functions, regardless of sex.