A genetically inherited sex chromosome abnormality only affecting females. Women with Turner's only have one X chromosome--their genotype is X0. These individuals are short in stature, averaging 4'7" and have distinctive webbed necks (i. E. , extra folds of skin). They have exceptionally small breasts and generally lack secondary sexual characteristics. Their ovaries do not develop normally and they do not ovulate. They are in a sense postmenopausal from early childhood and are sterile. In some individuals, there is slight mental retardation. Turner syndrome is rare--current estimates of its frequency range from 1 in 3000 to 1 in 10,000 females.