Opposites Attract in Human Search for Mate When it comes to choosing a mate, opposites really do attract, according to a 8razilian study that found people are subconsciously more likely to choose a partner whose genetic make-up is different to their own. They found evidence that married couples are more likely to have genetic differences in a DNA region governing the immune system than were randomly matched pairs. This was likely to be an evolutionary strategy to ensure healthy reproduction because genetic variability is an advantage for offspring, Maria da Graca Bicalho and her col1eagues at the University of Parana in Brazil reported. "Although it may be tempting to think humans choose their partners because of their similarities, our research has shown clear1y that it is differences that make for successful reproduction, and that the University drive have healthy children is important when choosing a mate." Bicalho said in a statement.