Research: Human friendships based on genetic similarities beyond the superficial
Friends often look alike. The tendency of people to forge friendships with people of a similar appearance has been noted since the time of Plato. But now there is research suggesting that, to a striking degree, we tend to pick friends who are genetically similar to us in ways that go beyond superficial features.
For example, you and your friends are likely to share certain genes associated with the sense of smell.
Full Story: Washington Post