Down Syndrome is a common birth defect that is usually due to an extra chromosome. It occurs because an extra chromosome is added. Nondisjunction is how it occurs. Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two.

Klinefelter Syndromes a genetic condition that results when a boy is born with an extra copy of the X chromosome. The presence of an extra X chromosome in males most often occurs when the genetic material in the egg splits unevenly. How Klinefelter Syndrome occurs is random events during the formation of reproductive cells in a parent. An egg or sperm cell may gain one or more extra copies of the X chromosome as a result of nondisjunction as mentioned in the slide before. Klinefelter Syndrome occurs to males.

Turner Syndrome is a condition that affects only girls and women, results when a sex chromosome is missing. It occurs as a random event during cell division in early fetal development. It only occurs to women.

Color Blindness is an abnormal condition characterized by the inability to clearly distinguish different colors of the spectrum. Color blindness can occur when one or more of the color cone cells are absent, nonfunctioning, or detect a different color than normal. It occurs more to males than females