The high frequency of people with sex chromosome aberrations is partly due to the fact that they are rarely lethal conditions. Like Down syndrome and other autosomal problems, sex chromosome gross abnormalities can be diagnosed before birth by amniocentesis and chorionic villi sampling. S ex chromosome abnormalities are gender specific. Normal males inherit an X and a Y chromosome while females have two X's. A single Y chromosome is sufficient to produce maleness while its absence is necessary for femaleness.
Female abnormalities are due to variations in the number of X chromosomes.
Male abnormalities are the result of irregular numbers of either the X or the Y chromosome or both. If they survive to birth, these girls have abnormal growth patterns. They generally lack female secondary sexual characteristics. Their ovaries do not develop normally and they do not ovulate. The few o cytes that they produce are destroyed by the time they are two.