What is the cause of klinefelters syndrome?

Klinefelter syndrome is a genetic disorder caused by the presence of an extra copy of the X chromosome in males. This results in a chromosomal makeup of XXY instead of the usual XY. The exact cause of this chromosomal abnormality is not fully understood, but it is believed to occur randomly during the formation of sperm or egg cells. Advanced maternal or paternal age has also been associated with an increased risk of Klinefelter syndrome.