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    Genes May Influence Friendships

    Genes May Partly Explain How People Choose Their Friends, Study Shows
    WebMD Health News
    Reviewed by Louise Chang, MD

    Aug. 7, 2007 -- Your choice of friends may stem, in part, from your genes, a new study suggests.

    The study, published in the Archives of General Psychiatry, doesn't mean that you're fated to be friends with some people and destined to dismiss others.

    But the findings do suggest that as kids mature into young adults, they may have a genetic inclination to pick certain types of people as their friends.

    "As we grow and move out of our own home environment, our genetically influenced temperament becomes more and more important in influencing the kinds of friends we like to hang out with," states Kenneth Kendler, MD, in a news release from Virginia Commonwealth University, where Kendler is a professor of psychiatry and human genetics.

    Kendler and colleagues interviewed about 1,800 male twins aged 24-62 born in Virginia and listed in the Virginia Twin Registry.

    The researchers asked the twins about the friends they'd had from age 8 to 25, splitting that time frame into several two- to three-year periods.

    The twins reported how many friends they had had in each time period who smoked, drank, cut classes often, used or sold drugs, stole things, or got in trouble with the law.

    Genes and Friendship

    Identical twins share all the same genes. Fraternal twins don't.

    In Kendler's study, identical twins were more likely than fraternal twins to make similar choices in their friends. So the researchers reason that genetics may play a role in choosing friends

    That doesn't mean that identical twins always chose the same type of friends. The findings aren't quite that iron-clad.

    But Kendler's team estimates that when kids are 8-11 years old, genes explain 30% of their choice in friends, with that percentage rising to about 50% from age 15-25, as people mature into independent adults.

    In short, the study suggests that genes may influence friendship, but genes aren't the final word on how people choose their friends.

    Since all of the twins were white men, it's not clear if the findings apply to other groups of people.

    • What attracted you to your best friends? Tell us about it on WebMD's Health Café message board.

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