BO, attraction, and sexual orientation

As reported in the Observer by Jessica D. Payne, Ph.D., scientists continue to find more evidence that body odor (BO) is a key component in determining sexual attraction.

Your BO is like a genetic fingerprint; everyone’s is unique. Even infants can smell the difference between their mother and other women. A person's BO is influenced partially by diet but largely by genetically determined Major Histocompatibility Complex (MHC) molecules. MHC is linked directly to the immune system.

Research has shown repeatedly that humans and other animals prefer to mate with partners that have

BO vastly different than their own. This unique MHC profile lets potential partners know that a mate has a different immune system. This evolutionary adaptation ensures genetic variation, resulting in offspring resistant to a wider array of diseases.

Differences in MHC and BO have also been connected to sexual orientation. A 2005 study published in Psychological Science, revealed that men and women, as well as homosexual and straight individuals, have very different BO preferences. One study took BO samples from the armpits of volunteers who used odorless soaps and refrained from foods like garlic, curry, and cumin. Another set of volunteers then smelled these BO samples and ranked them in order of preference. Homosexual men preferred the BO of gay men and heterosexual women. Likewise, the BO of homosexual men was least liked by heterosexual men and women, and lesbians.

Read more at the Observer