Genes May Influence Friendships
Genes May Partly Explain How People Choose Their Friends, Study Shows
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
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
"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.
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