Did you put on perfume or cologne this morning? Well if you did, you might not be attracting Mr. or Ms. Right. In fact, you may actually be attracting the wrong person. That's because attraction has scientifically been linked to smell. In fact, our response to olfactory cues actually helps us narrow down our choices of potential partners.

MHC (the major histocompatibility complex), a set of genes that controls the immune system and influences tissue rejection is especially critical. You are most compatible with a partner whose MHC is sufficiently different from your own. Oddly enough, studies show that couples with similar MHC's have trouble conceiving or an increased risk of miscarriage.

A study had females smell various t-shirts worn by different anonymous men, then pick the one that appealed to them most.

Most women chose ones worn by men with a MHC dissimilar to her own (=good). Those who chose the t-shirts worn by men with similar MHC (=bad) were often on birth control, where the daily dose of hormones can confound the MHC-smell detection system.

Going one step further, a chemist associated with the study "wonders if the Pill may contribute to divorce"¦ Women pick a husband when they're on birth control, then quit to have a baby and realize they've made a mistake." There's an in-depth description of the study & a scientific explanation here.

Of course, if you're not keen to trust your own MHC detectors, there is hope. ScientificMatch is an online dating service where you send in saliva samples and the program matches you with a mate with dissimilar immune system genes. It's only $1,995.95 a year for anyone except convicted criminals or women on birth control.

Learn more about what Diana learned today, here.