There are three reasons why people believe in God and or attend services. Some carry genes for just 1, others 2, and a few, 3 reasons. If you inherited all three, you have the God Gene.
The God gene hypothesis states that some human beings bear a gene which gives them a predisposition to episodes interpreted by some as religious revelation. The idea has been postulated and promoted by geneticist Dr. Dean Hamer, the director of the Gene Structure and Regulation Unit at the U.S. National Cancer Institute. Hamer has written a book on the subject titled, The God Gene: How Faith is Hardwired into our Genes.
Harvard educated geneticist Dean Hamer presents the case for the genetic basis of religious belief and spirituality. The book is extremely well-written and clear, especially for those unfamiliar with the study of behavioral genetics and molecular genetics. Hamer skillfully weaves an argument for the connection between our human capacity for profound religious experience, the brain mechanisms involved in such experiences, and the genetic basis for those brain mechanisms.