Homozygous; Inheritance; Heterozygous; Inheritance patterns; Heredity and disease; Heritable; Genetic markers

Genetics is the study of heredity, the process of a parent passing certain genes to their children. A person's appearance -- height, hair color, skin color, and eye color -- is determined by genes. Other characteristics affected by heredity are:

  • Likelihood of getting certain diseases
  • Mental abilities
  • Natural talents

An abnormal trait (anomaly) that is passed down through families (inherited) may:

  • Have no effect on your health or well-being. For example, the trait might just cause a white patch of hair or an earlobe that is longer than normal.
  • Have only a minor effect, such as color blindness.
  • Have a major effect on your quality or length of life.

For most genetic disorders, genetic counseling is advised. Many couples may also want to seek prenatal diagnosis if one of them has a genetic disorder.


Genetics is the study of heredity and how traits are passed along from parents to offspring. Genes are contained within the chromosomes found in the egg and sperm. Each parent contributes one half of each pair or 23 chromosomes to their child, 22 autosomal and 1 sex chromosome.