While basic science teaches that males have a set of XY chromosomes and females have XX chromosomes, this is not always the case. In uncommon instances, males or female babies can be born with less or more X or Y chromosomes than normal. One such example in males is Klinefelter syndrome where there is an extra X chromosome (i.e. XXY) which produces more feminine traits and sterility. In females there is one called Turner Syndrome where they are missing a X chromosome. Those who suffer from Turner Syndrome see traits liked a webbed neck and many health problems.