Chromosomes are structures formed by double-stranded DNA, inherited from both the mother and the father, wrapped around various proteins and condensed approximately 10,000-fold, becoming visible during cell division. A healthy male typically has 46 chromosomes, with the sex chromosomes X and Y denoted as 46,XY. In Klinefelter syndrome, there is at least one extra X chromosome. This extra X chromosome can originate from either the mother or the father. The primary cause of this extra chromosome is not parental genetic carrier status, but rather the failure of chromosomes to separate properly (non-disjunction) during the formation of egg or sperm cells.