What role do sex chromosomes play in determining the biological sex of humans?

Sex chromosomes play a crucial role in determining the biological sex of humans. Typically, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The presence of the Y chromosome triggers the development of male characteristics, while the absence of the Y chromosome results in the development of female characteristics. This genetic combination influences the development of reproductive organs and secondary sexual characteristics in humans.