As regards falling in love, the old wives’ tale has always indicated that opposites attract. The modern way of saying this might be: Heterosexual men and women with dissimilar genes are more likely to get married than people with a similar genetic heritage.
A recent study from the University of Parana in Brazil has found this to be true; people are more likely to become lovers if their genes share little in common. It seems that certain genes control some of the subconscious desires behind the choice of one partner over another, as a way of preventing inbreeding and boosting the immune systems of the lovers’ offspring.
Researchers at the university studied the genes of 90 married couples and found that their DNA in a key region of their chromosomes differed significantly from the same stretch of DNA in 152 couples chosen at random from the general population, who were neither married nor having sexual relations with one another.
The genes, called the major histocompatibility complex (MHC), are part of the immune system. If the MHC genes played no role in the choice of a mate, then similar differences between both sets of couples – the married and the unmarried – would be found. The statistically significant difference suggests that dissimilar MHC genes influenced whether men and women become attracted to one another.
It’s possible that the MHC genes have a subtle effect on body scents or pheromones which in humans play a part in deciding whether a man or a woman is subconsciously considered to be attractive to an individual of the opposite sex.
