Human genetics is a branch of biology and medicine dealing with heredity, especially attempts to explain the similarities and differences that exist between parents and offspring. In medicine, genetics plays an increasingly important role in the prediction, diagnosis, and treatment of disease.

Although hypotheses on the nature and mechanisms of heredity date to antiquity, genetics did not become an independent scientific discipline until the turn of the twentieth century. Through studies of crosses between garden peas, the Czech-born German monk Gregor Mendel (1823-1884) worked out the basic principles of inheritance, which he expressed in his laws of heredity. Mendel's work stimulated the first experiments in what is now known as classical genetics. These early studies developed into the eventual identification and demonstration of chromosome individuality, gene linkage, crossing over and the linear arrangement of genes in chromosomes.

The term genetics was actually first coined, in the...