According to an interesting study by the researchers at the University of Parana in Brazil, the "opposites attract" hypothesis actually does hold - most people are intuitively more likely to go in for a mate whose genetic constitution differs from their own.

Lead researcher Maria da Graca Bicalho and her colleagues said evidence shows that the fact that married couples are more likely to have inherent dissimilarities in a DNA region - managing the immune system - is probably an `evolutionary strategy,' which ensures healthy reproduction because genetic variability works to an advantage for the kids.

To arrive at the aforesaid conclusion of the study - the findings of which would be presented at the annual conference of the European Society of Human Genetics in Vienna - the Brazilian scientists studied data concerning major histocompatibility complexes (MHC) from 90 married couples, and compared them with 152 randomly generated control couples.

It was found that people with dissimilar MHC - a gene-dense area of the genome that largely governs reproductive success - were more likely to select each other as mates than those with similar MHCs.

Bicalho said: "If MHC genes did not influence mate selection, we would have expected to see similar results from both sets of couples. But we found that the real partners had significantly more MHC dissimilarities than we could have expected to find simply by chance."