The question arises as to how the sex of an individual is determined. Is sex determined by the number of X-chromosomes - with one X you are male or with 2 X's you are female? Or is sex determined by the presence or absence of the Y chromosome - the presence of a Y makes for a male or the absence of a Y produces a female?
The answer was provided by individuals resulting from non-disjunction of the sex chromosomes. Some individuals have 45 chromosomes and have only one X chromosome; other individuals have 47 chromosomes and have two X-chromosomes and a Y. The table below indicates the sex of these individuals. _____________________________________________________