This document summarizes human sex determination and sex-linked genetic traits. It explains that humans have 23 pairs of chromosomes, including one pair of sex chromosomes (XY for males, XX for females). Genes located on the X and Y chromosomes can determine sex-linked traits and disorders. Examples discussed include color blindness, hemophilia, and Duchenne's muscular dystrophy, which are more common or only present in one sex due to their location on the X chromosome.