(HealthDayNews) -- While married couples tend to look remarkably alike, they probably smell quite different, says David Bodanis in his book The Secret Family.
Each of us has a "personalized invisible halo" of chemicals that reflect unique aspects of our immune system, and that are detectable at a primitive, lower level of consciousness, says Bodanis. And women tend to pick mates with opposite smells in an apparent evolutionary attempt to give their offspring an inherited boost by having more immune variations to protect them.
Bodanis cites experiments in which women are asked to choose men they like from the smell of their slightly used shirts. "They almost always prefer those belonging to men with a different immune cloud than their own," he says, with one notable exception:
Women taking birth control pills make a 180-degree switch, preferring males with similar immune-system smells. When they stop taking the contraceptives, the female preference switches back to opposites, Bodanis says.
