Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Health & Balance

Font Size

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.

Today on WebMD

woman in yoga class
6 health benefits of yoga.
beautiful girl lying down of grass
10 relaxation techniques to try.
mature woman with glass of water
Do you really need to drink 8 glasses of water a day?
coffee beans in shape of mug
Get the facts.
Take your medication
Hand appearing to hold the sun
Hungover man
Welcome mat and wellington boots
Woman worn out on couch
Happy and sad faces
Fingertip with string tied in a bow
laughing family