Jim Lewis and Jim Springer were identical twins raised apart from the age of four weeks. When the twins were finally reunited at the age of 39 in 1979, they discovered they both suffered from tension headaches, were prone to nail biting, smoked Salem cigarettes, drove the same type of car and even vacationed at the same beach in Florida.
The culprit for the odd similarities? Genes.
Genes can help explain why someone is gay or straight, religious or not, brainy or not, and even whether they’re likely to develop gum disease, one psychologist explains.
Such broad-ranging genetic effects first came to light in a landmark study Minnesota Twin Family Study conducted from 1979 to 1999, which followed identical and fraternal twins who were separated at an early age.
“We were surprised by certain behaviors that showed a genetic influence, such as religiosity [and] social attitudes,” said Nancy Segal, an evolutionary psychologist at California State University, Fullerton, who was part of the study for nine years. “Those surprised us, because we thought those certainly must come from the family [environment],” Segal told Live Science. Segal described the groundbreaking research on Aug. 7 here at a meeting of the American Psychological Association.
Read the full, original story: Twins separated at birth reveal staggering influence of genetics