In a study performed out of Virginia Commonwealth University, K. Kendler performed a study to see if your choice of friends stems in some part from your genes. He and his staff interviewed 1800 male twins aged 24-62, who were all born in Va. The twins were asked about the friends they had from ages eight to 25. From that, the scientists then separated those years into many two- to three-year periods. They were asked which of their friends, if any: drank, cut classes, smoked, stole, did and/or stole drugs, or got in trouble with the law.
According to Kendler’s study, they believed when children are between the ages of eight to 11, their genes explain 30% of their choice in friends. Both kinds of twins were interviewed in the study, and all happened to be white males. Kendler believed people’s genes affect about 50% of all their friendships between 15-25 years old. Between those ages people are maturing into adults and are able to identify more with the kind of people that they themselves may be.
It was found that identical twins were more likely than fraternal twins to make similar choices in friends. Because identical twins share the same genes and fraternal twins do not, Kendler believed that genes influence who we’re friends with; although it’s not the final say on who we ultimately choose as our friends.