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At least one faith, according to one of its best-known scholars, formalizes the idea of gene-based spirituality and even puts a pretty spin on it. Buddhists, says Robert Thurman, professor of Buddhist studies at Columbia University, have long entertained the idea that we inherit a spirituality gene from the person we were in a previous life. Smaller than an ordinary gene, it combines with two larger physical genes we inherit from our parents, and together they shape our physical and spiritual profile. Says Thurman: "The spiritual gene helps establish a general trust in the universe, a sense of openness and generosity." Buddhists, he adds, would find Hamer's possible discovery "amusing and fun."
The Buddhist theory has never been put to the scientific test, but other investigations into the biological roots of belief in God were being conducted long before Hamer's efforts--often with intriguing results. In 1979, investigators at the University of Minnesota began their now famous twins study, tracking down 53 pairs of identical twins and 31 pairs of fraternal twins that had been separated at birth and raised apart. The scientists were looking for traits the members of each pair had in common, guessing that the characteristics shared more frequently by identical twins than by fraternal twins would be genetically based, since identical twins carry matching DNA, and those traits for which there was no disparity between the identicals and fraternals would be more environmentally influenced.
As it turned out, the identical twins had plenty of remarkable things in common. In some cases, both suffered from migraine headaches, both had a fear of heights, both were nail biters. Some shared little eccentricities, like flushing the toilet both before and after using it. When quizzed on their religious values and spiritual feelings, the identical twins showed a similar overlap. In general, they were about twice as likely as fraternal twins to believe as much--or as little--about spirituality as their sibling did. Significantly, these numbers did not hold up when the twins were questioned about how faithfully they practiced any organized religion. Clearly, it seemed, the degree to which we observe rituals such as attending services is mostly the stuff of environment and culture. Whether we're drawn to God in the first place is hardwired into our genes. "It completely contradicted my expectations," says University of Minnesota psychologist Thomas Bouchard, one of the researchers involved in the work. Similar results were later found in larger twin studies in Virginia and Australia.