Genetic material and information passed on from individuals of one generation to the next. Genetic material and hereditary are not synonymous; for example, a fertilized egg contains much cytoplasm that is non-genetic. Also, material passed from the mother to the embryo via the placenta is in a sense hereditary, but again not genetic.
See Behavior genetics, Co-twin method, Cytoplasm, Heritability, Menarche, Mendelian genetics, Nature-nurture debate, Non-shared environmental influences, Nucleic acid, Oligogenic mode of inheritance, Placenta, Self-differentiation