Abstract
Evidence has been accumulating from various fields of research that genomic imprinting, defined as the differential modification of genetic material depending on whether inheritance is from the male or female parent, occurs in mammals as well as in man. Human genetic diseases such as complete hydatidiform moles, triploidy, Prader-Willi syndrome, Angelman syndrome, and various cancers provide strong support for the important role of genomic imprinting in human development and represents a new mechanism for disease.