In this system, the sex of an individual<span> is determined by a </span>pair<span> of </span>sex chromosomes called the <span>gonosomes. Females typically have two of the same kind of </span>sex chromosome <span>(XX) and are called the homogametic </span>sex<span>. Males typically have two distinct </span>sex chromosomes<span> (XY), and are called the heterogametic </span>sex<span>.</span>
