Even though there are many probable causes of human disease, family history is often one of the strongest risk factors for common disease complexes such as cancer, cardiovascular disease, diabetes, autoimmune disorders, and psychiatric illnesses.
A person inherits a complete set of genes from each parent, as well as a vast array of cultural and socioeconomic experiences from his/her family. Family history is thought to be a good predictor of an individual’s disease risk because family members most closely represent the unique genomic and environmental interactions that an individual experiences. Inherited genetic variation within families clearly contributes both directly and indirectly to the pathogenesis of disease. Genes were no longer merely the key to understanding health: they had turn into the skeleton key for unlocking approximately all the mysteries of human existence. For virtually every aspect of life – criminality, fidelity, political persuasion, and religious belief – someone would claim to find a gene for it. Almost all inherited features or traits are the products of complex interactions of numerous genes. However, the fact that there is no one genetic trigger has not by itself undermined the claim that many of our deepest character traits, dispositions and even opinions are genetically determined.